A continuing problem with sick dojo loach, and now my emerald green Cory cat has the same illness 9/22/09
Hello,
I am still struggling with the problem Neale responded to in August.
<Oh dear.>
The latest news is one of my balloon belly mollies died last week, the one that gave birth a few weeks earlier.
<Too bad.>
I noticed that she was stuck to the filter and assumed she was dead, but when I unplugged it she swam away. Then shortly after I noticed she was swimming oddly, a little crooked.
<Physical damage, to the fins at least, perhaps more serious. Balloon Mollies are deformed right from the get-go, with a crooked spine and deformed swim bladder. They swim poorly even in the best of health, and Mollies generally are prone to poor health in freshwater tanks. A deformed, sensitive species...? No thanks -- I recommend against them.>
She would stay close to the bottom but swam up eagerly whenever it was feeding time. She got stuck on the filter a couple more times throughout a few days and then died. I wasn't sure this odd swimming was due to the filter mis-hap or if she was sick and weak before the first filter incident.
<Healthy fish don't get sucked into filters, so if you see a dead fish in a filter, it was moribund/dead before it got there.>
And four days ago my Cory cat (the only one) showed the same signs of illness as my dojo loach - red around the gill area and at the base of his fins. He was also swimming insanely and I saw rapid gill movement.
<Interesting that these are both bottom feeders. I wonder if there's something wrong with your substrate and/or water circulation. If this was me, I'd replace the substrate (or at least thoroughly clean in outside the tank, e.g., in a bucket using a garden hose) and then check the filter was shifting water along the bottom of the tank properly.>
I put him in the quarantine tank with the dojo loach and started Maracyn-2.
They have had four days of treatment now. The Cory cat developed mouth rot too, just like the dojo did. And yesterday I noticed a whitish lump on his underside. I'm going to try to attach a picture at the bottom of this e-mail somehow (I have not been successful ever at resizing pictures).
<Again, the mouth and the belly (and the whiskers, so check those) are in contact with the substrate. A dirty substrate promotes (though doesn't cause) bacterial infections by producing the conditions those bacteria prefer. One reason I like sand rather than gravel is that it's less likely to get dirty, and also less likely to physically abrade sore or sensitive tissues. The addition of Malayan Livebearing Snails to tanks with a sandy substrate is a good way to keep the sand clean and well oxygenated.>
I figured that since the dojo loach, although healed from mouth rot, was still looking a little pinkish all this time, that this bacterial infection was still lingering (or incurable and I should pick up some clove oil soon as you had suggested in the first place) and it couldn't hurt to do another treatment. The hole in his head hasn't gotten any bigger and looks like it is either just staying put or healing at a slow rate.
And here is all of the info about my tank:
(this is from my records from starting it up, figured I'd give you all the info - sorry if it's way too much)
55 gallons
first set up February 28th 2009 - I tried to do a fishless cycle and thought I was successful, though now I wonder.
on this set-up day I filled the tank, used Prime, poured some of my established 10 gallon tank water into the new tank, added purchased bacteria, added a tank decoration from the 10 gallon tank.
Day 6, I tested the water
GH 180
KH 120
PH 7.5
<Fine.>
Day 7 added water softener pouch for 7 hours and tested:
GH 120 (test strips hard to read, but wasn't the solid 180 color it was on Day 6)
KH 120/180 (test strips hard to read)
PH 6.5
<Why the water softener? Why are you lowering the pH? Let's be clear: a pH of 7.5 is ideal for most aquarium fish. Multiple reasons, but the important ones are [a] the filter bacteria prefer a basic pH, and [b] hard, alkaline water is less likely to experience pH variation than soft, acid water.
Unless you're breeding fish that specifically need soft water, it's best to leave hard, alkaline water as it is.>
Added the established 10 gallon tank filter, plus another tank decoration (from the 10gallon tank)
added two of my zebra Danios
added more purchased bacteria
<The bacteria are in the system; adding more largely pointless. I'd sooner add a big clump of floating plants such as Indian Ferns. These carry lots of helpful bacteria on their roots, so help cycle tanks, and more importantly, suck up ammonia and nitrite as they grow.>
Day 8 tested water:
GH 120 ? (test strips hard to read)
KH 40 ? (test strips hard to read)
PH 6
Nitrite 0
Nitrate 0
<Again, we have this dropping pH, likely because your carbonate hardness (KH) is FAR TOO LOW for a freshwater community. Remember, Mollies MUST have hard, basic water, at least 15 degrees dH (~250 mg/l calcium carbonate equivalent), and ideally much more. There are VERY few community fish that actually demand soft water, and you certainly wouldn't keep them with Mollies.
http://www.wetwebmedia.com/FWsubwebindex/fwh2oquality.htm
>
Day 11
ammonia read > .25
<No surprise. When pH gets below 7, biological filters start to work significantly less efficiently, and below pH 6, the bacteria don't work at all.>
Day 13
ammonia read .25 or less
GH 30
KH 40
PH 6
Nitrite 0
Nitrate the test strip was faintly pink, but basically zero
<Hmm...>
Day 15
ammonia .25
Nitrite 0
Nitrate 0
PH 6.5
KH 180
GH 120
did 8 gallon water change, added 55 mL bacteria
<Still got ammonia; the pH is low, the filter crashed, and that's likely one key factor here.>
Day 17
ammonia .25
<Again...>
Day 20
ammonia <.25
Nitrite 0
Nitrate 0
PH 8
KK 40
GH 120
added three red Serpae tetras (from my 10 gallon tank)
<Why adding fish?>
Day 23 and Day 24
ammonia 0
Day 25
had water tested at store, tested fine. purchased 3 dwarf gouramis/added to tank
<Wouldn't touch these fish with a bargepole, and in an unstable tank, their lifespan isn't likely very high. Golden rule: don't add fish while you're still trying to keep others alive.>
added 55 mL bacteria
Day 27
ammonia 0
Day 36
Nitrite and Nitrate both at 0
Day 38
added 3 Rasbora tetras, changed Right filter
Day 42
8 gallon water change
Day 61
8 gallon water change
Day 67
8 gallon water change, changed Left filter this is about where I stopped recording. I tested during this time and everything was at zero. I Figured the tank was cycled.
<Maybe.>
My tests today read:
PH 7
Nitrate 0
Nitrite 0
Ammonia 0
ALK KH 180
Hardness GH 150
<Better. But still, let's get the pH to 7.5, if necessary by adding suitable amounts of Rift Valley cichlid salt mix; I'd say about 1/4th to 1/3rd the dose recommended for Rift Valley tanks should be fine. Don't alter the pH directly; just change the carbonate hardness, and the pH will follow, and in a stable way.>
I use an AquaTech filter - I had made my own filter cartridges for a few times, using the white fluffy filter material (it was the only kind the pest store sold) and charcoal, using one of the plastic pieces from inside a store-bought filter on the inside. I stopped doing this in case this is why the fish are getting sick.
I feed with:
TetraMin Tropical Tablets, "the rich mix for bottom feeders"
Omega One Natural Protein Formula shrimp pellets
Omega One Super Color Flakes (natural protein formula)
Tetra Min Tropical Flakes
I use Seachem Prime with every water change, adding it to the buckets before pouring into the tank
temp 76-78 F
I currently have in there:
4 Rasboras
2 black neon tetras
3 cardinal tetras
1 balloon molly
1 Pleco
all seem fine, except the Pleco goes a little pale in patches once in a while, but this was happening from the beginning and I thought it might be normal for them when they were resting (I had never had one before).
<The patches are mucous, and often a reaction to water quality problems.>
I think in my original email to you (or it is in the Disease Emergency post)
I mentioned that there were to mollies (or platies, I can't tell the difference) that I introduced a few weeks before the Dojos got sick. One of them died about a week after, and the other one died suddenly a week after that. When I scooped it out of the tank I saw that it had a bright red circle about 4mms wide on its side. This is what leads me to think that it was this fish that introduced disease to my tank, but I'm obviously no expert.
<Well, I am an expert, and I'll tell you if you keep lowering the pH like this, any livebearers you add will die. End of story. For optimal results, aim for moderately hard, moderately basic conditions: pH 7.5, 10-20 degrees dH (that's about 175 to 350 mg/l calcium carbonate equivalent). That will keep livebearers happy, while remaining acceptable to a wide range of community fish. Yes, Neons and Rasboras and the like come from soft water habitats, but they don't share them with Mollies or Platies! So you have to use your noodle a bit here, and figure out which species are most sensitive to water chemistry issues (livebearers) and act accordingly.>
The first dojo loach that died had those red spots, but smaller and not as bright, all over his body when he died.
<Still a bad sign.>
At least the Cory cat's getting sick has given the dojo loach some welcomed company in the quarantine tank. He did perk up to see his old friend and they hang out together most of the time now.
<Hmm...>
Of course I would love to save the two sick fish, but I'm even more concerned about the future of my main tank. There must be something wrong with it, especially since my Cory cat is sick with the same symptoms. Where do I go from here?
<See above.>
Any hope for the sick fish or is it time to let them go? the Cory cat is still quite active, and the dojo loach isn't acting like he is anywhere near death either.
<Likely can, will recover given good conditions and right medications.>
Thank you so much,
Hilary
<Cheers, Neale.>
Pictures below - the dojo loach is looking good except for pinkish hue around gills and back end of body. Tough to see in the picture though.
You can see the hole in his head though - I hope it isn't a terrible case.
It seems to be staying put.
<Nothing came through. Please be sure to attach ~500 kB images to your e-mail. Images that are too big cause problems for us.>
Re: a continuing problem with sick dojo loach, and now my emerald green Cory cat has the same illness 09/24/09
Thank you for your reply - I have some questions and explanations and have tried to make them easy for you to find by using lines to separate my words from the original e-mail.
<OK.>
I wasn't able to get the resized pictures to attach to this e-mail and hope that it is acceptable that I cut and pasted them at the bottom.
<Nothing came through. Cutting and pasting images into e-mails doesn't always work. Do use the "attach" button on whatever your e-mail program is.>
I have sand substrate. It is children's play sand. I was told by a fish store employee that it is great because it is a more natural color and less expensive than the marketed kind for aquariums.
<Provided the sand is [a] smooth and [b] chemically inert, you can use whatever you want. Sand comes in two grades, "sharp" and "smooth", and sharp sand will damage your fish. As for the chemistry, the sand needs to be lime-free. Personally, I use smooth silica sand from garden centres as a 100% safe alternative. Play sand, pool filter sand, etc. may be fine, but there are no guarantees. The play sand from one shop may be different from another, so I can't give you any assurances. If the sand feels smooth, that's good, and if it doesn't react with acid (e.g., vinegar) that's good too.>
After Googling and reading the same online, I went ahead with this. I washed it thoroughly, in small quantities, by running water and stirring it until the water was nearly clear. Was this a mistake to use this kind of sand and do you still believe I need to change it or wash it again?
<Provided the sand is safe to use for the reasons stated above, cleaning it is more a visual thing. Most folks find that the silt in bags of sand makes their tanks murky for a few days, but nothing a water change and a good, strong filter won't fix. Replace/clean the mechanical filter media after the first week because that's where most of the silt ends up/>
and I am soooo uncomfortable with the idea of introducing snails into my tank again, as I had way too many in my 10 gallon at one point after one hitching a ride in with a fresh plant.
<Snails convert organic matter into baby snails. If you have too many, then you have other problems.>
This is also why I am super hesitant to ever bring fresh plants into my tank again.
<Non sequitur. There are plenty of ways to kill snails on plants before you put them in your aquarium. Snail-killing potions are sold in aquarium shops and work well as "dips".>
I had "pond snails" I believe.
<Typically Physa and Planorbis spp.>
Are they the same as Malayan Livebearing Snails?
<No, these are Melanoides spp.>
I will introduce the snails if you really think I should though...
<I have Melanoides snails in all my tanks. I find the good they do -- as substrate cleaners and aerators -- easily outweighs their nuisance value.
While they do breed quickly, a combination of physical removal, predators, and simply ignoring them works a treat. Clea helena, the Assassin Snail, is a great snail population limiter.>=
Well, I freaked out that my 55 gallon tank had harder water than my established 10 gallon tank and it was harder than the water straight from the tap. This confused me and figured I should get the water the same hardness as the established 10 gallon was. So I was trying to soften it just a bit, not lower the pH. I had heard so much about not being worried about or try changing the pH that I didn't think it a big problem that the pH changed (and figured it would level out with water changes). Lesson learned.
<Cool.>
Why adding fish? Because I thought that adding the three fish (transferring from the established 10 gallon tank) would help the cycle to continue at a safe rate. I was more paying attention to the ammonia/nitrate/nitrite tests than the other areas.
<Ah, I see. Generally, so long as a tank has a few fish in there, the cycling process will continue happily enough. Adding extra fish is of marginal value, unless you plan to *dramatically* increase the population of fish in there at some point. For example, if you cycled with a couple of Guppies, and then added an adult Oscar, that would probably be bad!>
I didn't realize I was trying to keep others alive at this point...just thought I was helping the bacteria multiply at a safe rate for the fish.
They did not last super long (and they were so darn territorial with each other it was annoying to have them in there, too).
<Yes, many schooling fish stop being schooling fish when in groups of less than six, and in some cases, they become outright nasty.>
I am having trouble finding Rift Valley cichlid salt mix here. One store sells "cichlid lake salt",
<That's the stuff!>
and she told me that all of their salts will adjust the pH, not the carbonate hardness.
<She's wrong. By definition, these salts raise the pH precisely because they're raising the carbonate hardness. It's the carbonate hardness that creates the "stuff" that makes the water basic. It's the carbonate hardness that "mops up" the acidity.>
If I did more frequent water changes for a while, will that help??
<Up to a point, yes, the more water changes you do, the less background acidification becomes an issue. But this gets tedious, very quickly, so think about what you're trying to achieve here: an easy hobby that involves nothing more than daily feeding and water changes every week or two.>
I hope that doesn't sound like a stupid question. Or is this something that I would need to add to my tank on a fairly regular basis? (if I can find it - I suppose I can order it online somewhere)
<Do read here:
http://www.wetwebmedia.com/FWsubwebindex/fwh2oquality.htm
There's a recipe for making your own Rift Valley Cichlid Salt Mix for pennies a time. It's easy to do. For a regular community tank -- as opposed to a Rift Valley cichlid aquarium -- you'd use a smaller dose than described there; try reducing the amounts to one-fourth to one-third the amounts listed.>
I'm worried about this fish if he is reacting to water problems and am so frustrated I can't find the salt you mentioned. I noticed today that he was pale on about half of his body, and then when I turned the light on, most of the rest of his body went pale. I checked back later and he is dark as could be....tried to take a picture when he was pale but he had disappeared when I returned with the camera.
<Oh. For what it's worth, Plecs are quite tough fish, and given good conditions, generally recover from stress quickly.>
I'm sorry and feel stupid saying this - but I don't know what 10-20 degrees dH or the equivalent you mentioned means.
<Simply being precise. The other way of saying this: on your test kit, there'll be a scale of some sort, running from Soft to Moderately Soft to Moderately Hard to Hard to Very Hard, or words to that effect. For Mollies, the water MUST be Hard to Very Hard. For community fish, Moderately Soft to Hard is generally fine. In other words, Mollies only mix well with those community fish tolerant of "Hard" water, i.e., things like Platies and Rainbowfish, but not so much Rasboras or Cardinal Tetras. You have to pick and choose tankmates for Mollies very carefully.>
Possibly this is information on the comparison card for the liquid test tube version of the tests (and not test strips)? Aside from borrowing a friend's test tube testing kit for the last test I did to get you accurate info, I haven't used those for anything but ammonia (but plan to purchase a kit soon).
<I see.>
Would this Maracyn two be the right medication?
<Either than, or regular Maracyn should work. They treat different bacteria, on the average, people find trying Maracyn first works best, and only use Maracyn 2 if that doesn't work. But your own mileage may vary.>
This poor loach is now enduring a third treatment since this all started, and although he seems to be doing okay, he still has pink/red at the base of his side fins and a pinkish tone to his gill area. He looked this way when I put him back in the main tank and got sick again so I of course don't want to put him back until he's 100%. It seems that his recovery has plateaued and I don't know what to do about this. The Cory cat seems to be responding well to treatment thus far, but still looks red/pink and I assume he will have the same plateau.
<Likely.>
okay, here is what I think the right sizes for you to see. The dojo picture doesn't look all that clear, but anywhere where it looks darker/pinkish is the pink that I am talking about that isn't going away.
I am cut and pasting them into the email and I hope this works.
<Didn't. If all else fails, try some free image hosting service such as Flickr, and include the link in your message.>
Thanks so much for your time.
Hilary
<Happy to help. Cheers, Neale.>
Re: a continuing problem with sick dojo loach, and now my emerald green Cory cat has the same illness 9/25/09
A link to the pictures! what a smart idea - here it is.
http://www2.snapfish.com/thumbnailshare/AlbumID=2062389007/a=32233289_322332
89/otsc=SHR/otsi=SALBlink/COBRAND_NAME=snapfish/
<I think you're meant to send an invitation to view this online album. As it is, I had to join Snapfish. Normally, we don't have time to go through hoops for this sort of thing. But it's a nice sunny morning here in England, so I joined up. Anyway, your fish don't appear to be especially "sick" as such, though the Corydoras looks a little underweight (if you can see the belly, it's concave, which isn't a good sign). My feeling is that these fish may have a mild bacterial infection, but it's more than likely we're talking about an environmental reaction. Variation in pH, a dirty substrate, marginal water quality may all be issues. In particular, take the time to review tank maintenance. Sand needs to be kept clean, and the best way to ensure this is to check there's a good flow of water along the bottom of the tank. Use a turkey baster to pipette out detritus between water changes. Feed your catfish and loaches their own food, ideally at night, so that they're not subsisting on leftovers; a good all-around food for both species would be Hikari Algae Wafers.>
Thanks again for your help. I have a few final questions
<Fire away.>
If my dojo loach continues to stay pinkish, what do I do? The two fish have had 7 days of powder packet treatments of Maracyn-two thus far. The instructions say to continue treatment until signs of illness are gone.
This could be a while if ever and I can't imagine the medicine is something good long term.
<I can't see anything obviously wrong with this Weather Loach. They can appear a little pink when the light shines through the thinner parts of their body, and if there's something amiss with the environment, they may appear irritated. But essentially these are hardy fish, provided they are maintained at below 25 degrees C (77 F). The same for Corydoras, and in fact I'd keep both species at the cooler end of the range, 22-24 C being ideal.>
And, do you suppose this sickness came about more because of the pH being below 7.5 or because there is some disease living in my tank that I still need to deal with?
<pH itself is rarely something that causes sickness unless it [a] fluctuates wildly within a few hours or [b] is outside the tolerances of a particular species. Loaches and Corydoras are fine between pH 6 to 8, so the value itself isn't an issue. But if exposed to pH that varies a lot, that can stress them. One key issue often overlooked is the toxicity of ammonia at different pH levels. In the acidic range, ammonia is less toxic than in the basic range, so if the pH goes from 6.5 to 7.5, while the pH change itself might be harmless, the sudden increase in toxicity of a small amount of ammonia in the system can cause severe stress.>
Can I treat the main tank with anything to make sure there isn't anything lurking in there waiting to cause more trouble?
<Right now, I'd finish the cause of meds you're on, and then concentrate on providing good, stable water conditions.>
How long would you to treat these sick fish before giving up?
<They honestly don't look that sick to me. Perhaps it's these photos?>
Until the hole in his head completely heals (how long does that take, anyway)?
<Should heal within a few weeks, should conditions allow.>
Until he is no longer pink? Both? The loach has been sick/pink for about six weeks now, poor guy.
<Are you sure it's simply not his normal colouration? Unlike Finrot, the classic bacterial infection, the fins on this fish are intact. If he had Finrot, I'd expect ragged fins.>
He doesn't look miserable now, at least, but I sure don't want to keep him in the 10 gallon hospital tank forever. The last time I thought he looked good to go and I put him back in the main tank, he was sick within four days and back in the hospital tank (and with a hole in his head appearing a few days after that).
<I see.>
I dropped some of the sand in a bowl of vinegar and saw no reaction. I am hopeful then that it is not the substrate that caused this problem and that I don't need to mess with it.
<Cool.>
I have a hard time killing snails (or I should say I just can't do it) and will need to look into this Assassin snail if I go this route. Though I am picturing the slowest predator/pray chase I've ever seen, ha ha.
<Prepare to be surprised! When the Assassin Snails kick into gear, they're remarkably brisk.>
Thanks!
Hilary
<Cheers, Neale>

Sterbai Corydoras with White Lump on Nose 4/14/2009
Hi There
Two days ago I discovered that two of my five Sterbai Corydoras had lost their barbells and both have a white lump on the tip of their nose. The lump appears to be solid, see attached pictures.
I've removed them from the community tank and put them into my 25L holding tank. As per the LFS (here in Australia) I have begun treatment with Tri-Sulfa tablets. I've also added an airstone to the tank, in case they need extra oxygen. The other Corys and community fish appear to be fine.
Prior to the Corys getting sick, my community tank details are:
1. Water parameters
Temp: 28C
PH: 6.8
Ammonia: 0
Nitrites: 0
Nitrates: 5
2. Tank set up
Size: L 36' (92cm) X W 14' (36cm) x D 19' (50cm)
Substrate: As seen in above pic, small round smooth gravel
Filtration: Aquaclear 50 (HOB)
Furnishings: 2 logs (aquarium decoration bought at LFS), 2 slate rocks, a terracotta pot, a terracotta plate, 1 large piece of driftwood, 3 Amazon sword plants
Tankmates: 2 Bolivian Rams, 1 SAE, 6 Dwarf Neon Rainbows, 6 Neon Tetras, 9 Ember Tetras
Tank has been established for 11 months.
Does anyone on the Crew know what this is, and have I begun the right treatment?
Thank you in advance for any advice on this matter.
Deanna
<Deanna, the treatment is very simple. Take out the gravel; put in smooth (not sharp!) silica sand or an aquarium sand expressly suitable for burrowing fish (many aren't, e.g., Tahitian Moon Sand).
http://www.wetwebmedia.com/fwsubwebindex/nicebottoms.htm
What you are describing is extremely common. All that happens is that the Corydoras burrow into the gravel, or try to at least, and they damage their snouts. Bacterial infections set in, and the whiskers rot away. Corydoras shouldn't be kept in tanks with gravel, though a lot of people do so (and yes, they all have Corydoras with missing whiskers). Cheers, Neale.>

Albino Aeneus Cory with Unknown Affliction -- 8/8/8 Hello there. I was referred to your site by a friend and I hope you can help me out. I've been keeping/breeding/raising tropical aquarium fish for a few years, but have yet to come across anything like this. A couple months ago, I noticed one of my Albino Aeneus Cory females was getting very plump in the chest. Since this normally occurs prior to spawning, I thought nothing of it. However, the area kept getting larger, so I started monitoring her more closely. Since the group had not spawned recently, I attributed it to being egg-bound, or possibly constipated/having a blockage. I have upped my tank maintenance, fasted, and generally just made things as perfect as possible. Last weekend the group spawned, and she was right there with them, basket full of eggs and all.....she's not egg-bound. I have also seen her passing waste, so she's not constipated/blocked. Unfortunately the 'bubble belly' remains. I have seen her with the light behind, and her chest area honestly looks hollow, like a water bubble. I don't believe it's air as she has no issues with floating and I've never seen her fight to stay on the bottom. Other then the large chest which makes her rest funny, she is a typical Cory. Roots around in the sand, eats and schools with the others, darts to the surface for a gulp of air and general acts perfectly normal. I'm attaching two pictures of her in hopes you can help. Please note, she has always had the kink in her tail so that is not a new issue. Thank you in advance for any help/advise you can give. Worried Cory Mom :) <Unless someone has a better idea, I'd put this down to a tumour. Not uncommon among ornamental fish, and possibly related to either dietary or environmental inadequacies. Given these are albino fish, they're also likely to be inbred and genetically weak (if nothing else, albinism makes animals more vulnerable to damage from UV light, but that's not going to be a problem indoors). If the fish is otherwise healthy, I'd not worry overly much, but be prepared to painlessly destroy the fish if it shows signs of suffering. Cheers, Neale.>

Sick Cory cats? 4/8/08 Hi crew, hope all is well. I recently (Thursday) added 2 Corydoras Schwartz's to the 3 I already had in my 20 gallon freshwater tank. They came from the same small LFS and I was told they were the last of the group the first 3 came from, so I added them to the same tank (I know my first bad move). <Certainly can be...> I have had the others for over a month with no issues although I lost one the day after, but I truly think I was just inexperienced and did not acclimated correctly. So now I have 5 and they have been acting so cute, shoaling and everything! <Cool!> Last night I noticed a white looking area on one Cory's head which runs down behind the 'mask' to form a V when you look down from above. Actually a couple of them seems to have a 'V', but only one has the area on top as well. I am not sure at all if this is normal markings, as I don't remember it from before. <Does vary, but there are also look-alike species... often the problem with Corydoras.> I watch them every day and night. I love the way they appear to wag their tails like puppies. <Preaching to the converted... I enjoy keeping, breeding Corydoras very much. More sheer fun than any fancy-pants reef fish!> From all my reading last night and today I can't find anything like this so I am sending you some pictures hoping you can either tell me what to do ASAP, or put my mind at ease. Hopefully the latter. These pictures are the best I could get, these buggers are quick! <Too small really to tell... would prefer one decent sized photo around 400 px square rather than these.> I am pretty sure the one with the white on the head has been here for better than a month as he doesn't hide from me. The new ones run when I come up to the tank, while my others obviously know I am the food God and love to see me coming at dinner time. I did have some Algae issues from over feeding but I did a 50% water change and severely restricted light for a week or so, and I am still keeping short light times to discourage a reoccurrence. I was feeding 3 Hikari wafers a night! <My Corydoras love these too. Corydoras eat a lot of algae in the wild, and this aspect is often overlooked by fishkeepers.> But now I only feed 1 every other night with 1 little HBH shrimp pellet. I break all of these up into little pieces or they play tug of war with them! <I'd say one Hikari algae wafer (around the size of a small coin) per night for 5 catfish is about right. Maybe skip one night so they can earn their keep cleaning up the tank a little. While it is certainly true big catfish do best when fed only a few times per week, I'm not sure this is true for Corydoras which are simply so much more active.> The other nights I feed 2 1/2 shrimp pellets. These are little pellets, nothing like the Top Fin ones that are huge! They eat everything in under an hour so I feel they are not being over fed since they nibble a lot and play during feeding. Once or twice a week I throw in a couple of brine shrimp or blood worms(frozen). They seem very happy although I have one that hides a lot in the tree stump. This one is the biggest and I think she is a female, but that is not one with any white and I watch her more than the others for any sign of disease since she does hide. She just always has. When I had 3, 1 of the others would stay with her constantly, but now she stays alone mostly. <Corydoras frequently divide into subgroups, with one female to one or more male. The males will follow the female about. If they're happy, you'll often see some species of Corydoras spawn even in community tanks. Not sure Corydoras schwartzi spawns in aquaria though.> Not sure of these kind of dynamics but I can only guess it has to do with the make-up of the group. Here are my parameters:ammonia-0nitrite-0nitrate-Under 20chlorine/Chloramine 0GH-150KH-180pH-7.8 <All fine. Do keep the temperature on the low side though, ideally around 22 C and certainly no more than 25 C.> I do 20% WC's weekly along with vacuuming with battery powered Penn Plax vacuum. <Slightly more water changing would be recommended. 25-50% is my preference in freshwater tanks. Cheap, easy way to ensure good health.> I only use prime for my water conditioning, although I do add Bio Spira with new fish. <Redundant; a mature filter will adjust to reasonable increasing in stocking virtually at once all by itself.> It is a twenty gallon tall tank with a Penguin 150 filter. The only thing I can come up with besides that these are normal markings (then why don't they all have them) is that it could be a fungal or bacterial infection, or rubbing I have read about in wild collected specimen. <Fungal infections should look distinctly odd in texture, typically white and fluffy. While not uncommon on Corydoras, they are usually associated with serious physical damage and/or poor water quality.> Gee, that would mean my LFS lied to me. While I am sure not all that uncommon, it would really upset me as they have the best looking fish around and they are a small independent store that even carries Bio Spira. Thanks so much for you insight and this site, people like me who just don't have the experience to recognize these things appreciate all of your hard work very much. I spend a lot of time researching so I can only imagine how many years it took you to learn all you know. Thanks for sharing it with us. Debbie <Need a better photo to say anything sensible about the "white" patches. Cheers, Neale.>

Re: gray spots on Orange Neon Cory 12/7/07 Hi, I have yet again another problem with my Corys. <Oh?> Last week my 30 gallon female Betta/ Cory tank experienced a bout of something that was best described as Epistylis. I was in contact with Neale and with his great advice and help I think we cleared that problem up. All is well in that tank. <Good-oh.> Neale suggested as a general rule for all my tanks to do 50% WC per week, which I have started doing. I was only doing 25%. I treated the Betta/Cory tank with Jungle's Tank Buddies for Fungus and then after two treatments of the Fungus meds, added Pima Fix for the Cory with healing fins and barbels and I have noticed regrowth on both areas. Should I do more Pima Fix and for how long? Something else? <I'd keep using it until the fish are 100% healed. Pimafix is pretty mild stuff and unlikely to cause any problems.> I am also running a 55 gallon community tank with two dwarf Gouramis, two gold gouramis, 1 blue three spot and 1 Opaline Gourami, 5 Schwartzi Corys, 6 Orange Laser Corys, 7 scissor tail Rasboras, 1 pair black mollies, and a pair of orange platies. <Ok.> The tank has lots of live plants, Fluorite bottom about 3/4 deep, an HOB filter and a sponge filer rated for 40 gallons. After I removed the carbon, as suggested, I placed 3/4 cup of Zeolite in the HOB filter for ammonia and left the coarse sponge like screens in for filtration, OK? <Zeolite is almost as useless as carbon. Zeolite removers ammonia. Nothing else. That's all it does. If you have a biological filter that is working properly, the Zeolite isn't adding anything useful to your filtration system. It's just as waste of space and money. Zeolite is primarily for tanks where biological filters can't be used, e.g., soft water tanks at pH <6, or hospital tanks set up at a moment's notice.> Water parameters are temp. 80-82 degrees, Ammonia 0, nitrate 0 and nitrates 0. PH is about 7.2 before and around 7.5 right after WC. <Ooh, a little on the warm side. Aim for 25C/77F. Corydoras especially don't like overly warm water.> Here's the problem. Two of the Orange Laser Corys have what look like gray patches on their heads. The patches are not perfectly round, one has a crescent shape patch and the other's is sort of oval. Both have a lighter, as in color and thickness, patch near one gill. These appeared after the 1st 50% WC, which I am careful about as regards to matching water temps. <Water changes shouldn't cause any problems if done properly. Water temperature isn't really a factor, because Corydoras LOVE cool water splashed into their tropical tanks. It's how you get them to spawn. But you do need to check you're using a suitable dechlorinator, for example one that removes Chloramine if you live somewhere that Chloramine is used.> The patches are not like fibers, about 1/4" in diameter, though irregular. They are not moving, I'm sure not Velvet, certainly not Ich. Do I have a fungus or a bacterial infection going on? <Sounds like it. Treat with combination Finrot/Fungus since we don't know if it's a bacteria or fungus at work here.> I treated the tank with Jungle's Tank Buddies for Fungus as I did the other tank since the color of the spots appeared, initially, the same as with the other Corys in the 30 gallon tank, but the results were totally different. The Orange Corys appeared to be responding to treatment, but then the gray soft ( as in non reflective or velvety) appearance of the spots seems to dissolve, for lack of a better way to explain it, and then the spots or patches seem to be concave as if there was just a wound left underneath. BTW, I treated twice, as per directions which were four day treatments with 25% WC between applications. The spots were concave after the first treatment, but no improvement and no change in the lighter affected spots near the gills. <Hmm...> I am at a total loss as to what to do now at the end of the second treatment. I have looked everywhere for an accurate picture of the condition on the web and nothing seems to match exactly. It could be sap, it could be Columnaris, it could be?????? But, now it doesn't sound like Epistylis! <Could be Columnaris (a.k.a. "mouth fungus") but could be something else, too. Use a combination Finrot/fungus medication and chances are good it'll clear up, even if you don't know what the precise problem is.> I should mention that the tank also had something else going on in it and the Jungle Buddies fungus cure worked in conjunction with medicated food. The largest Blue 3 spot Gourami had two red spots, one near the anal fin and one on the head. Hence the medicated food and they have now healed. Bacterial infection due to poor water quality? <Most probably.> One of the Dwarf Gouramis had what looked like it might be the start of a spot near it's mouth and that has also disappeared. More like an abrasion, but never got red or raw, just scales that didn't look "right". <Quite possibly damage from fighting.> None of the Schwartzi or other Orange Laser Corys have shown any signs of the spots and all but one Orange Cory is still very active and eating. No signs of fin or barbel damage in any of them, including the two affected. <Good. Treat and wait.> I have been to three LFS and bought whatever I can lay my hands on, Help! I think I've read so much on the web and your site that I'm now paralyzed with indecision as to my next move! <Combination Finrot/Fungus medication is the way to go.> Thanks for any advice and especially this site. It is so informative and the first place I go to now when I have any questions regarding fish, aquariums, plants, you name it. It is the best out there. Polly <Glad we can help. Good luck, Neale.>

Re: gray spots on Orange Neon Cory 12/07/2007 Hi Neale, <Hello Polly,> Sorry I didn't write back immediately. I did another 50% WC, instead of the recommended 25% on the Jungle Fungus Tank Buddies and dosed the entire 50 Gal tank again. This will be the third round of meds. <Sheesh... that's a lot of medication. I'd be switching brands, if that's an option for you. I've learned the hard way that sometimes one medication works where another fails. Mostly this is with Whitespot/Ick, but perhaps worth considering here.> The spots on the two orange Corys are now whiter and a bit ragged looking. One Cory is lethargic and the other is still active an eating. None of the other Schwartzi or orange Corys are affected with any signs of this condition. <White stuff is usually dead tissue, whereas grey stuff is mucous. So given this is white stuff, I'm guessing we have necrosis going on, meaning that things are pretty bad. If this was me, I'd be thinking about saltwater dips as a supplement. These are basically baths made with aquarium water and 35 grammes of salt (any kind, really) per litre. You dip the fish for a period of time, once per day. The idea is the salty water cleans the wound and destroys the fungi/bacteria causing the problem. It can work very well, but Corydoras are not especially salt-tolerant, so you'd have to do this carefully. Perhaps dipping at first for 1 minute, and seeing how things go. If the fish is fine, try two minutes the next day. Salt-tolerant fish can stand up to 20 minutes, and this does a great job, but in this case, I'd be limiting myself to no more than 3-5 minute dips.> I didn't mean that the spots appeared after the WC and the WC was the condition was probably already working it's black magic on those two Corys and the WC was most likely a lifesaver for the others in the tank, who certainly would have become infected too had it not been for the WC. Sorry. <Agreed. Water changes normally only do good.> How many times should I stick with this med if it doesn't appear to be working? And, what antibacterial med should I use with it? Should it be after this treatment or in addition to the treatment? ( the Jungle Fungus med does state that it treats both, but I don't see any signs of improvement on the Corys. ) <Stop using one medication when you start with another, unless it *expressly* says you can use in combination with some other named medication. My gut feeling is you're going to need a Maracyn-type systemic antibiotic to fix things here. Such drugs are available over-the-counter in the US, or you can get them through a vet. Maracyn is Erythromycin, each Maracyn tablet is apparently 200 mg Erythromycin and meant to be used one tablet per 10 gallons of water. So if you can't get Maracyn itself, an appropriate concentration of Erythromycin should work just as well. I'm not a vet though! So take this suggestion for what it is, my best guess!> I just spent an hour looking at each of the fish in the 50 gal tank and noticed that one of the yellow Gouramis is not tolerating the treatment too well. She/he is hanging out at the top of the tank in the corner and not interested in food. It was active and hungry this morning. The red/blue dwarf Gourami is not looking too active either. His abrasion, or whatever it was, is healed, but now he looks like he's growing a little double chin below his mouth! Nothing is red or raw, but it is worrisome to me. <I'd stop feeding, and also do something to increase oxygen concentration. Slightly lowering the temperature will help (to 74F/23C) as will adjusting any filters or air pumps to maximise circulation of the water. Lowering the water level slightly so that the spout of water from the filter makes more splashing can help, too, by driving off CO2 and improving oxygen absorption.> The reason I had the Zeolite in the filter was that I had to remove the carbon and thought it might control any ammonia during the first two treatments. Now I realize that with the sponge filter and the plants and other items in the tank, they will take care of the ammonia problem. Is that right? Sorry to be so dense. <Yep. Healthy filter bacteria do a better job than Zeolite anyway. But if you've had a lot of Zeolite in the filter, potentially the filter bacteria will be under-developed, so do check for signs of ammonia. That'll correct itself within a few days though, because you should have at least a semi-healthy population of filter bacteria. So it's not like cycling the tank from scratch.> You asked if I was conditioning the water. Yes, I use AquaSafe, but recently read that it might acidify the water more than other products. Is that true? <No idea, and can't imagine it'd be that big of a deal.> Is there something that is better for hard well water for conditioning in your opinion? <No. It's mostly about Chloramine, which some water suppliers add to the water. A few dechlorinators don't treat it properly, and you end up with extra ammonia. I'm not aware of any specific problems with well water.> I also age the water for at least a day and have four 5 gal buckets, and 5 or 6 gallon containers set aside. <Probably redundant, but certainly not doing any harm.> I keep reading different people's methods for their WCs and wondered if it's OK to heat a bit of tap water, condition it and add it to the aged/conditioned water to heat it up? <There's nothing wrong with mixing hot/cold water right from the tap. Dechlorinators usually treat copper from the pipes. The only bad water is water from a domestic water softener. Fish don't like this stuff at all.> I had to do that this morning to do the 50% fast WC before I caught the 10 AM boat to make a doctor's appointment. Now I'm wondering if it has anything to do with the two gouramis not doing so well tonight? <Unlikely, and in any case should settle down. I once added almost ice-cold water to a tank filled with parent and baby cichlids. I was in a rush, and not thinking. The fish went crazy, rolling onto their sides as if stunned. An hour later they were fine. Fish are actually quite robust animals, and when we see problems, it's usually because the problem has beaten their immune system and blown into something serious. Provided you keep the fish healthy in the first place, they almost never get ill. Honest!> Also, really stupid question now, how is it people use Python systems straight from the tap and add the conditioner at the same time and get that right? <The basic idea is you add the dechlorinator to the tank first, and then add the water so it instantly mixes with the dechlorinator in the aquarium water. I'm old school. I use a plain vanilla hose pipe and suck the water out to start the siphon.> Is that a good practice, or are they doing it out of necessity with large tanks or multiple tanks? <Lots of people like them. I'm not one of them though. I tend to mix rainwater with tap water, or salty water with tap water, to create specific water conditions. So Pythons aren't terribly useful for me.> right now to age is impossible and I was just wondering if I could do it too without adding more problems. <Should work fine. Ageing water isn't terribly important these days, especially if you use a decent dechlorinator and have lots of circulation in the tank to mix the old and new water properly. Anything that makes water changes easier is a good thing, because you'll do more of them in less time and with less frustration.> Thanks again, and I'll keep you apprised of what happens next. PS. Angelfish still looking good, just did their weekly 50% WC tonight, bought them their own 28 gallon tank and will move them out of the 12 next week. <Very good.> Polly <Cheers, Neale.>

Re: gray spots on Orange Neon Cory 12/9/07 Neale, <Polly,> OMG, we're into metrics...I don't do metrics well, too old for the change over! lol Nearest I can figure out, with a dilution of that percentage for Corys and rounding off, would be 35 grams to 1 litre = 2 tablespoons per 1/3 US gallon H2O, would that be best? Is that right even? <Ah, metrics are actually easier for this kind of thing, because normal salinity, 35 parts-per-thousand, is identical to the concentration in weight measurements, 35 grammes per litre. As it happens, I have a little computer program designed for calculating salinities and switching between metric and US units, called "Brack Calc", which you can download and play with at the link below. By my reckoning, normal seawater salinity is about 4.7 ounces of salt per US gallon. http://homepage.mac.com/nmonks/aquaria/aqua_soft.html You'll have to experiment yourself and see how that works out in teaspoons.> Both Corys doing badly now and I fear the worst. Should I do a 50% WC on the 55 gal tank to remove the Jungle Fungus Buddies med and do the E-mycin treatment instead, or let this treatment run the remaining three days of it's course? <Change water and switch medication. Nothing to lose, everything to gain.> Isolate them and do the E-mycin in the QT tank? <Leave them be. The stress of moving them won't help.> Or, continue treating the 55 gal since there might still be something contagious there? <I'd treat the quarantine and the display tank.> I know what you said last time, and that was the entire tank at this point, so am leaning in that direction, but want to hear you say that's right. <I almost always treat tanks rather than specific fish, except for things like saltwater dips, and even then the dip is to assist the medication, not replace it.> I'm going to change the positioning of the HOB filter and sponge filter to change the direction of the water flow a bit and then add an air stone near the bottom of the tank to increase the oxygen and movement. I used to have one there before this all started to turn sour and took it out as it ticked off the dwarf red Gourami, "Il Duce", who has been using all his spare time building floating plant islands and building bubble nests, also a great pain in the butt when it came to constantly clearing the slots in the bottom of the filter uptake, but he would have his way. <Hah! We see who wears the trousers in your household...!> I tried to control this plant yanking obsession of his by taking a piece of tubing and turning it into a floating circle for him, plopping his plant material in it and floating it in one corner away from the filter, but he plays with it too much and the other gouramis like stealing his plants for their own islands. We now have three floating islands for the gouramis! Does keep the floating stuff in check, but the air stone pushes them around and they are not happy. Tough love is called for I think. lol <In the old days people use to break Styrofoam cups into segments, and Gouramis seemed to love building nests under them. They (the cup fragments) float really nicely, curve upwards, gathering plant bits underneath them. Worth a shot.> The blasted heater is hard to adjust and I am going to swap it out for a different heater and see if it can more closely control the temperature level. Why is it that you can find a heater that works perfectly, from one company, buy another of the same brand and get totally different results??? UGH! <Heaters are often annoying. I find that some designs -- those with rubber caps over the entire adjuster-end of the device -- often become stiff with age. The effect of water and/or hardness I suppose. I prefer the ones where the adjuster knob is free from the rest of the cap. In any case, one old trick is to use two under-powered heaters for a tank. That way, if one gets stuck, it isn't powerful enough to boil the fish. Conversely, if one fails completely, the other heater will keep the tank from getting dangerously cold. So if your tank needs 150 W heater, get two 75 W heaters instead.> I had lowered the water level a bit after that fast WC yesterday and figured I would leave it that way for awhile to increase some splashing, and really a good rationalization since I didn't have the time to add the remaining two or three gallons before the boat time. <Cool.> Thanks for the info on the Python and WC ideas. Indeed, not worrying about ageing the water makes life easier and better with more WCs for the fish. <Agreed. Fishkeeping should be a low-impact hobby. If you're spending more than 45-60 minutes a week on maintenance, you're doing something wrong. The whole point of the thing is to relax, watching the colourful beasts swimming about merrily (or violently, if you're keeping cichlids).> Thanks, Polly <Good luck, Neale.>

Re: gray spots on Orange Neon Cory 12/10/07 Neale, <Polly,> lost the two orange Corys in the night. <Ah, too bad.> I hadn't changed out any water or the meds as of last night and when I got up this morning and checked the big tank, found the two dead Corys and the other orange Corys were acting distressed. One was "running" up and down the side of the tank and hid if I came within sight! The others didn't flash or swim up and down, they just hid on me too. I reckoned that the meds might be stressing them. Took out 10 gallons of H2O and then added that and the water I hadn't put back in two days ago. Makes about 12-13 gallons in to dilute some of the meds. Is it possible that it took two days for the meds to distress this much? <Possible. Unlikely, but possible. Most medications are more or less toxic to fish, and we use them on the basis that *most* of the time they kill the infection before they seriously harm the fish. But some fish are peculiarly sensitive to certain medications. I've not personally experienced this with Corydoras, but it may happen with some species and some medications I've not kept/used.> I see a bit of brightness, as in orange or reddish, near the gills of one of the orange Corys, which is hard to detect with their coloring, but the others aren't showing any signs of red at all, just hiding on me in their little cave. <I REALLY need a photo to understand what's going on here. We've pretty much run through the list of common infections & their treatments.> The other fish seem to be normal, just a bit curious as to all the new water coming in and old going out, but otherwise OK. The 5 Schwartzi Corys are still oblivious to anything different happening, are acting normal and eating, nothing unusual on their bodies or in coloration. No fin or barbel loss, redness, nothing that I can see with the naked eye or the magnifying lens and flashlight. This is true of the orange Corys too. No fin or barbel loss either, no spots or patches of fungus like things. <Good.> The only thing I can imagine is that it was too much medicine going in and I should have done either a lighter dose or perhaps pulled the two affected out of the tank and waited to see what would happen???? I tried to dose with the amount of water actually in the tank rather than the tank's potential capacity. <Sometimes it is worth doing half-doses of medication. If the infection is slight, half-doses might help with reduced risk of problems. But if the infection is serious, you usually need the full dose to get the desired results.> I have to believe something else is going on in this tank and there is something I can't see, or one is a carrier of something in there with the rest. What else can it be? Could they have some little parasite that is in the gills that is undetectable? <I really don't know. Without seeing a photo of the fish in question, it's very difficult to be sure what's going on.> OR, is this a progression of a disease which is just taking out the weaker fish in sequence? <Certainly possible. This is precisely how Neon Tetra Disease works through an aquarium, knocking off a fish at a time, usually once every few weeks.> I'm totally baffled by this. The orange Corys came through the Ich outbreak without any of them catching a spot, have been looking really good until this hit all at once. Probably not all at once, you're saying, but brewing away in the depths of the tank and had I done the 50% WCs all along this wouldn't have happened. <Ick is usually a very obvious disease, and if it becomes fatal, it is obviously serious with white spots all over the fins and flanks. So we can probably discount this. Ick can make fish sensitive to secondary infections, and it is possible that this has happened here. Since "secondary infections" covers a lot of ground, it's difficult to identify the pathogen without access to a microbiology lab. Pseudomonas and Aeromonas are the two commonest bacteria, but there are many others.> Should I still try the E-mycin or just do more WC tomorrow? <I'd try the Erythromycin at this stage. Do two big water changes before though, to flush out as much old medication as possible. Maybe 50% tonight, then 50% tomorrow morning, and then dose the tank. Do take care to siphon up any detritus in the tank while you're at it. The 'cleaner' the tank, the better the antibiotic will work.> I'm starting to wonder if the Dwarf Gouramis had something up with them when we introduced them to the tank about three weeks ago. <Dwarf Gouramis are fish I would never, ever keep. They are notorious carriers of viral and bacterial infections, to which they usually succumb very quickly. Whether said infections can jump to catfish I do not know. Anything's possible I suppose, but I haven't heard this particular thing happening before.> They were Qt'ed for two and a half weeks, showed no signs of anything, but were stressing each other out so much that we finally added them to the big tank. They have been doing OK, but might have carried something in as yet undetected. <Indeed. Hard to say.> Thanks for the quick reply, once again, Polly <Cheers, Neale.>

Re: gray spots on Orange Neon Cory 12/11/07 Neale, <Polly,> I have tried all day to get a picture of the Corys, but they aren't cooperating one bit. When they do come out they are in constant motion and once the flash on the digital goes off, they go into deep hiding. <Oh.> Interesting thing is that they look and act normally, when they come out of their cave and rock hidey holes. This is only when they don't see us and they were frantic to eat when I fed the tank! Could I have cleaned the tank bottom too well? LOL Doubt it, but its not nearly as bad, which didn't appear that bad, to begin with. ( also, we've kept their end of the tank without lights for most of the day to make them more comfortable about coming out.) <No, don't worry, clean is good!> I shined the flashlight on all the oranges, when I could sneak up on them, and they all look the same color in the gill area. Think it's a trick of the light with their Neon orange coloring. Depending on how they turn, the gills look reddish or gold. Now I think I must have panicked and they don't have a gill problem. They all look exactly the same in the gills. <Good.> My mother, whose chair is right next to the tank, has been watching them closely all day and she thinks they are more out and about than yesterday, none have "run" up and down the tank side, flashed or done anything unusual except the hiding. She admitted to dropping a little food into the tank to see if they'd come out and sure enough, they rushed out from under their cave, ate and then swam right back in when they were done. The Schwartzi are not acting this way at all and they all ate together, including our large blue 3 spot Gourami who loves the algae pellet too. That didn't upset them either. <Very good. I'm glad your Mom is getting involved. The more people who recognise healthy fish/behaviour, the better. It's like having more spies! You get a heads-up on problems when someone else in the family says, "Gee, that Catfish is looking a bit odd this morning".> The Schwartzi and the oranges used to like to hang out at the end of the tank with the sponge filter and I've changed the sponge filter to the other end of the tank. It seems unlikely that that could be the problem. I haven't read that they are territorial. The Schwartzi are now more at the sponge filter end of the tank. The oranges in The Cave. <Corydoras aren't remotely territorial. They live in schools of hundreds of fish in the wild, often mixed species groups but not always. Some species won't school together, and simply ignore each other.> Still no marks or spots or growths on them and no deterioration on barbel, fins or tails. Just this weird behavior. Could they be so stressed from the loss of the two other Corys? <Stressed is perhaps not the word, but Corydoras do become more nervous/less day-active when kept in too-small a group.> There were 6 and now are four, but there are still the 5 Schwartzi Corys who they eat with during their feeding frenzy. <Ah, I'd aim for at least 6 of each, ideally more.> This brings up the question of whether they are getting a proper diet. I give them half of an algae pellet every day and every other day a few shrimp pellets. They scavenge for any leftover food from the top feeders and I have cut back some on that food as I thought we might have fed them too much. They are fed twice a day and sparingly. Could their diet be deficient? <No. It's almost impossible to starve fish because they have very, very low food requirements. Most of what we eat is effectively "wasted" on thermoregulation (I think it's 80% of the calories, but I'd have to check). Most fish do not control their body temperature this way, instead relying on the warmth of the water to keep them at the right temperature. All they need per day is enough food for movement and growth. Literally a single flake will supply this for a small, inch-long tropical fish. Anything else is a bonus. Corydoras also eat a lot of plant material in the wild, and will graze on algae and decaying plant matter.> I'm totally baffled by this turn of events, think I will not add any other meds to the tank right now and wait another day to see what happens. Is this wise or should I really do E-mycin to the entire tank without any other indications? <If we think the gills are normal, and the fish show no other symptoms, it may well be time to leave things be.> If this is just some stress related behavior I really don't want to add to it. I'm going to do another big WC tomorrow and hope that they aren't even more reclusive, but it will make the water conditions even better and I'm hopeful that it will make them more comfortable. <Water changes are good!> Will try and get some pictures, but don't know if they'll be more cooperative or not. Thanks again, Polly <Good luck, Neale.>