Nassarius snails "eating" sea hare? 09/29/10
Good Day, Crew,
I am always amazed by our reef tank. It is incredible how one small change can have major effects on the balance of life in the tank. This is a long one, I apologize in advance. Looking back at my reef journal I have seen a very interesting story take place. About a year ago we had snails deaths.
My large Nassarius snails had disappeared over a period of time, so I bought about 20 small dark Nassarius snails. We kept finding their empty shells. Even my 4 Turbos snails died.. Now, I never saw any shady snail behavior, I just found the empty shells, and a few weird little
<predaceous>
snails. Salty Dog helped me ID a couple nasty little whelks. They must have come with the Nassarius. I never replaced the snails. About six months ago we took a yellow tailed angel out of the tank, and within a few weeks those large Tonga snails started showing up again. How funny. I suspect the angel nipped their siphons, and that kept them hidden. So now just a few days ago we bought 20 Trochus snails, and a sea hare.
<What species Aplysiid?>
The moment the snails were in the water the Tonga Nassarius erupted from the sand and jumped on the Trochus like a tiger on a new York strip.
<Zow!>
What a bummer. A fascinating but expensive bummer. A few Trochus got away, but they are being picked off. The sea hare also got nibbled on. It grazed for a few hours on the rocks (ahem, hair algae) and grazed it's way to the substrate. I found 9 Tonga Nassarius snails on it. I brushed them off, and placed the sea hare up high on rocks.
<Won't work. Will be hunted down, consumed>
It started secreting aqua colored ink,
<Not good for your system, tankmates>
like smoke, but kept grazing along. We have not seen the sea hare for 48 hours. I also only see about 4-6 Tonga Nassarius snails. I fear the rest are chewing on the sea hare somewhere. I suspect these Nassarius are very hungry due to a recent upgrade; the contents of our a 90 gallon to a 180 gallon, and I replaced all the sand with new LS. I wish I had kept the old sand but I was certain it would be foul. It was not but the 180 was already full with the new LS. Oh, well, live and learn. I did put a few cups of the old sand into the 180. Any thoughts would be appreciated. I am wondering are these Nassarius worth it, should I feed them, and if you think I should keep them, and supplement their diet, how many would be good for a 3-4 inch deep sand bed that is 2x5 feet?
<Some folks like some species of Nassarius... I am by and large NOT a fan of overloading captive systems w/ gastropods... they have their downsides... as vectors of disease, polluters, and predators. Read here: http://wetwebmedia.com/snailscavsel.htm>
And just so you know we intended to return the sea hare if the hair algae disappeared.
<There are species sold in the trade that are inappropriate. Read here: http://wetwebmedia.com/SeahareSelF.htm
and the linked files above>
My sons love sea hairs, but I have always said no due to the lack of hair algae. They are delighted at the algae issue!
My thanks, Victoria
<My welcomes, Bob Fenner>

Hair algae and pistol shrimp aggression towards sea hare? Hello, I was wondering if you can offer some guidance. Before I begin, my tank info is as follows: 29g Nano reef (running 1 year); approx. 25 lbs. live rock; 5g RO water changes every 7-10 days pH 8.3/salinity 1.024/iodine 420/calcium .06 ammonia/nitrite/nitrate/phosphate = 0 water temp. fluctuates between 80-84° Corals: trumpet coral, toadstool leather (2), branching frogspawn, cluster of xenia, Ricordea florida 5 polyps, asst'd. Zoanthids (approx 6-8? wide cluster) Livestock: 1 percula clown, 1 yellow watchman goby, 1 Rainford's goby, 2 pistol shrimp, 2 lettuce Nudibranchs, 1 dwarf sea hare (deceased) Over the past few months, I've been battling a problem with hair algae covering the live rock and back wall of the tank. Some of the Zoas are starting to get suffocated by the stuff. I've tried blue leg hermits, Mithrax crabs, and Cerith, Astrea, and Mexican turbo snails at different points in time. The crabs hardly made a dent. With regard to the snails, they've all been extremely lethargic following acclimation (hardly moving around), then slowly die off. I took a water sample to my LFS to see if they could give me any clues. Their results were similar to mine above, and their only guess was that the water temperature could be a cause of the snail deaths. <Your nutrients are likely measuring 0s *because* of the hair algae growth. They are consuming them. As for the snail deaths, how did you acclimate them? These animals are very sensitive to changing water conditions (even more so than fish and corals). Please see here: http://www.wetwebmedia.com/snaildisfaqs.htm> I bought 2 lettuce Nudibranchs to help cut down the algae, but have had similar results as with the crabs. Then I was told by the LFS that sea hares were better for consuming hair algae. I bought one and for several days it seemed to be doing well, constantly scouring the live rock. One evening, however, I couldn't find it. After searching with a flashlight, I saw it in the back of a rock cave in the clutches of one of the pistol shrimp, which was going at it with its smaller pincers. I scooped up the alive but injured sea hare and tried to place it high on the glass, away from the shrimp, but it was too weak to stick. I submerged a perforated container and placed him inside so the shrimp couldn't get it. But by the next morning, it was dead. <A lot of the sea hares sold to the hobby are cold water animals that don't live long in tropical tanks. Please see here: http://www.wetwebmedia.com/seaslugsel.htm> The tank gets fed daily, and I often see the pistol shrimp come out to snatch flakes from the water column, so I don't believe they're malnourished. Your answers to other pistol shrimp FAQs on your website state that predatory behavior by pistol shrimps towards snails and crabs isn't uncommon. I read somewhere else that sea slugs and Nudibranchs taste bad, so they usually get left alone by predators. Your thoughts? <They might not all taste bad.> The lettuce Nudibranchs are unmolested and seem healthy, one even laying eggs often. Although I like the interaction of the watchman goby with the pistol shrimp, I'm inclined to trap the shrimp and remove them. <Hmm, I would not remove the shrimp in hopes of saving the sea hare. And I would not seek to solve this hair algae problem with invertebrate herbivores. Please see here: http://www.wetwebmedia.com/algaeconMar.htm> I really want to get this hair algae problem under control. Any suggestions? <Please see the link above.> Thanks, Chris <Best, Sara M

Re: Hair algae and pistol shrimp aggression towards sea hare? 4/30/08 Sara, Thank you for your prompt reply. To respond to your follow-up questions: 1. A few posts within the FAQ on snails (that you referred to me) mentioned magnesium toxicity/overdose as a possible cause of snail death. One suggested poor quality salt mixes could be a source of high magnesium. Would ?Instant Ocean Salt? be considered acceptable quality in your opinion? <Usually, yes, but if you are having problems, you should measure the magnesium and consider trying a different salt (such as Reef Crystals, made by the same company, but generally a better salt)> With the exception of occasional doses of iodine (levels tested periodically), no other additives are put into the tank. Could anything else be the cause of elevated magnesium levels, based on the info provided? <Hmm, not that I can think of...> 2. The snails were acclimated by floating the plastic shipping bag in display tank (I acknowledge that using a QT is preferable, and admit I do not have one) in which they were shipped for 15-20 minutes, then opening the bag and pouring ½ oz. or so of tank water into the bag every 5 minutes until full, then discarding half of the water in the bag and repeating the cycle until bag is full again. Final step is placing the snails in the tank and discarding the bag along with the water inside. Total acclimation time is around 1 ½ hrs. In the same snail FAQ, there was a post where you suggested an acclimation method involving a bowl and wet paper towel; or in the alternative, placing the snail on the glass side of the tank above the water level, allowing it to lower itself into the water at its own pace. Do you suggest I use this method? <IMO, It's worth a try for future snails.> 3. If the sea hare was a cold water creature and the 80-84 degree water temperature was the cause of death - as opposed to predation - isn't it more likely it would have acted sick or lethargic from the start? The sea hare was active and seemed to be eating, scouring the rock and glass during the 5 days before I caught the pistol shrimp clawing? it. <It's hard to say. It could have been solely the shrimp's fault. But all the same, the slug would have likely begun to decline anyway.> 4. I read the algae control article you referred to me. The control methods outlined several factors, one of which was the amount of nutrients in the water. My existing 3 fish get fed flake 1x/day (food totally eaten in under 1 minute). Also, I do 5g RO water changes every 7-10 days. Is the above routine ok? <Normally, yes, but you have a problem...so, something needs to change. Your tank might be overstocked. Nano tanks can be especially touchy in this respect.> Water flow is handled by the ?stock? Bio Cube 29 pump, plus an additional in-tank powerhead. Lighting is by one actinic and one 10000k (72w total, bulbs replaced every 6-9 mo.) running between 9:30 a.m. and 5:30 p.m. daily. Would modifying this routine help combat the algae without affecting the corals? Mr. Fenner's article indicates that most runaway algae problems are due to excess heat and temperature fluctuations. I would hope to find a solution to the problem without spending several hundred dollars for a chiller or via higher monthly a/c bills. <If your temp is staying between 80-83F, that should be ok.> As mentioned, my water temp. is currently hovering near that upper threshold. Your thoughts? <I don't think this is a temp. problem as much as a nutrient control problem. Again, these things are all more difficult to deal with in small volumes.> Current filtration methods include live rock for biological, protein skimmer, bag of carbon/Purigen, and regular weekly cleaning of the filter pads of particulate buildup. The only other control methods are regular brushing/plucking/turkey basting of the rock and back wall of the tank. <I hate to have to tell you this, but if this just a little hair algae, you might just have to "deal with it." Algae is a part of the ecosystem in "real life." Changing salt mixes *might* help with the algae too...you never know.> Thank you again for your guidance, Chris <De nada and good luck, Sara M.>

Aiptasia & Sea Hare comp.... & Bio. alg. contr.    2/3/08 Although our 55 gallon FOWLR has been doing fine (fish growing & happy, no death, stable water) I have three nickel sized Aiptasia and some hair algae. Can/will the sting of an Aiptasia injury or kill a Sea Hare? <Won't be the best combination but certainly not the best solution for both problems. For the Aips see here: http://www.wetwebmedia.com/marine/inverts/cnidaria/anthozoa/aiptasia/aiptasia.htm. And the causes of the Hair Algae must be addressed first. The Sea Hare will just be recycling the nutrients the algae use. Read on Nutrient export etc. Olly>

Re: Sudden Appearance of a Bright-Pink, Flat Anemone! Seaslug/Hare comp.  3/6/07 Hi Bob <Angela> It has disappeared now and I will probably not see it again for another 2 months.   <?> I have looked at some pictures of button polyps and other Zoanthids, but mine only had approximately four or five little stubs around the outside of its 'face' and then another 4 or 5 a bit further in to the centre, and they were very short, and pointing out from the centre not upwards.  I am planning on getting a digital camera soon and so may catch an image in the future. <Good> When you said "do investigate the biology of this animal."  Did you mean the sea hare? <Yes> I have looked into it.  The store said it was Dolabella auricularia <The most commonly offered species> and from the pictures I have seen on the internet I believe this to be true.  I got it to eat all of my hair algae.  Now that all of the hair algae is under control I feed it dry seaweed everyday.  Do you agree with this level of care? <Mmmm> I have read that they can produce ink if threatened and that this isn't toxic, it just acts as a smoke screen. <Not so> Is there anything else I should know about it other than what I have found on your site?  (paranoid). <Do keep your eye on this animal, indeed all your livestock... as usual> Regarding the pink, possible Zoanthid; if it is one of these could it be a danger? <By itself? Unlikely> I have nightmares that I will come down in the morning and it will have swollen up to a foot across and eaten all my fish!! <Heeeee! Sorry... not probable> Thanks again Angela PS:  As sad as it is no I have not got one single Reefing friend...... <Mmm, unusual... perhaps a wider search, appeal on the Net... BobF>

Sea hare sel., comp.  12/30/06 OK, so after moving my tank (150g Berlin, 250lbs live rock, light bio-load) I had a huge outbreak of long green hair algae. Covered everything. Tried cutting back on the light, but I only achieved making it's color less attractive. After reading all I could, I decided I didn't want to go with scraping, chemical, etc....but add a natural solution. When weighing out the pro's & con's of such grazers, I settled on a sea hare, <Mmm, what species?> as it seemed to be the most voracious grazer. I wasn't so worried about it dying, as my tank is quite healthy and there is much for it to eat....... but with such a nocturnal creature, how on earth would you know if something that you rarely (if ever, lately...) see? <Mmm, the results of their night-time foraging?> Also, in a 150g, how much pollution/death could I be facing if I do not find the body? <Could be appreciable depending on the species, size... your filtration, maintenance...> 250lbs of rock is a pretty sizable pile to dig through. Thanks in advance, my briny friends!   -Pat <Do take care to try a tropical species (not a cool/coldwater one), that is, and stays small-ish. You have read here?: http://www.wetwebmedia.com/algaeconMar.htm and the linked files above? There are other "biological means" to consider... Bob Fenner>

Seahare comp., fdg. Hi Bob Another new question for you......Does a Sea Hare care what it has in its mouth? <Mmmm> That may sound really stupid but I have a Zoanthus colony with a very fine hair algae (green, massively invasive) encroaching and I believe smothering. If the Sea Hare chooses to eat the algae, will it also eat the polyps in the same mouthful? <I do think Aplysiids care... and Zoanthids are very toxic... Do read here: http://wetwebmedia.com/seaslugsopisthobranchs.htm and the linked files above... many Seahares are misplaced in aquariums... and elsewhere on WWM re Zoanthid comp.> Best wishes as always Sarah
<RMF>