not growing fishes, gen. and cichlids 09/29/08
Hi WetWebMedia crew, i have a question concerning my pet blood parrot, and jack Dempsey. i have kept them for over 1 and a half years. They are still only 5 inches.
<Blood Parrots are hybrids, and their maximum size is very variable. In theory they should get to as much as 20 cm/8", but often they stay much smaller. Jack Dempseys (Rocio octofasciata) should reach up to 25 cm/10", but inbreeding over the years means that they're often much smaller, and on the average 12-15 cm/5-6" is typical. Unfortunately, it's a case of "you get what you pay for" with cichlids, with too many breeders pumping out inbred fish out of undersized parents. Good quality cichlids are expensive, and if you want the best, you either approach serious breeders via clubs or else order wild-caught stock from your retailer.>
I feed them a varied diet containing krill, insects, dried food, and shrimp.
<All sounds great.>
I clean their tank once a week and the tank is clean. They seem pretty healthy. I keep them in a pretty big tank, i believe 45-50 gallons.
<Should be adequate for these fish.>
Thanks for your help.
<Broadly speaking, the secrets for getting cichlids to grow properly are [a] to keep the nitrate level low via generous water changes; and [b] to feed a little but often, perhaps 2-3 meals across the day, but each meal being quite small, a snack really. That said, I suspect genetics may have much more to do with your observations than anything else. Cheers, Neale.>

Juvenile Emperor Angel That Won't Grow  11/21/06   Dear Bob and Crew   I bought my Juvenile Emperor Angel over a year ago.  As far as I can tell it has not grown at all.  My friend bought one at the same time, and his is three times larger than mine.  These are the African caught Emperors so they are black bodied, rather than blue.  Is this something you have come across before?  Will it grow at all, or do you think it has some growth deficiency?  I have no problems with any of my other fish.   Thanks so much for your help   Claire <Mmm, there are a few (classes) of growth-limiting factors that might be at play here... Metabolite build-up feedback loops, social/negative interaction with tankmates, nutritional deficiency syndromes... Is the system "large enough", foods fresh/supplemented? Do you do regular water changes, use chemical filtrants, have adequate foam fractionation? I take it from the above that other species (not listed) are growing... Please read here: http://wetwebmedia.com/FWSubWebIndex/GrwLmtChems.htm and the linked files above. Bob Fenner> How much bigger? Mysterious limitation of fish growth...  SW   6/13/06 I have had a yellow tang and a blue angel for almost 3 years.  They are each about 3 inches, <... A "Blue Angel"... not the species I'm thinking... at three inches in as many years> and they have been this size for a long time.  It appears they have stopped growing.  Will they get any bigger? <Should... have>   My tank is a 125g with 25g sump and 130 pounds of rock, and I feed a small amount once a day (plus there's plenty of algae for grazing). Other occupants include a royal Gramma, sixline wrasse, percula clown, green Chromis, and sand-sifting goby.  Also have 6 Mexican turbo snails (awesome algae eaters).  Recently lost a 2+ year old chalk Basslet for no apparent reason (possibly just old age?) <Mmm, do live longer than this...> and also lost a lawnmower blenny (maybe the Turbos ate all his food?). <Perhaps> Water parameters have been consistent for years (SG 1.019, nitrate 10, ammonia and nitrite zero). <One factor here is your artificially low specific gravity. I would keep this closer to near seawater strength (1.025)> Anyway, I would love to get another angel or two. <... not in this size system> Possibly a flame or other dwarf and a juvenile French.  There would be three different genera (holacanthus, Pomacanthus, and centropyge), of three different sizes (ultimately the French would be biggest, followed by the blue and the dwarf).  Will this work? <Not a good gamble, no> I know French angels can grow pretty large, but nothing seems to get too big in my tank.  If my tang and blue angel can stay relatively small, might that be the same for a French? <Please read here: http://www.wetwebmedia.com/FWSubWebIndex/GrwLmtChems.htm and the linked file above. There is something going on here limiting the growth (and likely health) of your livestock> One more question-can you ever have too much coralline algae?   <Yes... to the exclusion of other desired life, excessive removal of alkalinity, biomineral...> Maybe it's the lighting, but my rocks are so purple that they look almost fake. <... You need to reveal more re your "chemical pouring history" here... I suspect you've got some sort of supplement habit... that is at play. Bob Fenner>

Re: How much bigger?     6/13/06 The blue angel in question is Holacanthus bermudensis. <Ah, yes... then this is some type of "stumping" for sure> Anyway, this fish along with the yellow tang are both thriving. <Though "bonsai'ed">   They look and act perfectly, eat everything voraciously, even seem to be friends with each other.  Is there really any problem with them not growing to their "expected" size? <Very good question (as I don't know and am curious re as well)... Such doesn't seem to be the case with "miniaturization" of many domestic animals...> Would there be any problem adding just a dwarf angel to this tank? <Too much so IMO... though if I were so inclined, I'd definitely go with a tropical West Atlantic species... perhaps a "dwarf dwarf" (C. argi, C. aurontonotus...)> It seems to me that a holacanthus and a centropyge are totally different size, shape, and color, so they should be able to coexist. <Yes... but your tank size is really not large enough for even just the Blue...> As for the coralline, I never supplement anything into the tank. <... I wonder... what your source water and salt mix result in in terms of alkalinity, biomineral content...?> The only thing that ever goes in there is food (frozen and flake, alternated, very sparingly).  How would I know if I have too much coralline? <The "bio assay" you mention. The apparent dwarfing of some of your livestock, the loss of others... Bob Fenner> Re: How much bigger?   6/13/06 I guess you are stumped more than my fish.  It's a rare question for sure if Mr. Fenner does not have the answer.  Thanks for your help as always. <Heeee! Stumped much more often than it appears! BobF> Can a shark's growth be stunted - 4/28/04 To whom it may concern, <Paul at the helm tonight> I stumbled across your website and found some conflicting ideals. <OK> I myself am a biotechnology student, <Excellent. What school?> and being a shark enthusiast, have enquired to my Marine Biology faculty <from the school which you are going?> as to whether or not shark growth is inhibited by surroundings (i.e.: small enclosure = small shark). I have been told that such stunt growth is the case, even in sharks. <Well, I am of the opinion that there is little true science in reference to whether an animals growth is stunted based on its holding tank/environment. here is a direct response developed by the three shark caretakers from the Monterey Bay Aquarium (where I volunteer weekly): Hmmm...differences between biologists that study sharks, but do not keep them in captivity and those that study sharks and actually keep them in captivity long term.  The whole story of fish being growth inhibited by the size of their container is not accurate.  They may develop stunted growth patterns, but they continue to grow.  An example of stunted growth patterns might include the bowing in of pectoral fins or hunch spine.  If sharks are limited by their enclosure, then why do public aquariums constantly get calls from people trying to donate sharks that have out grown their tank? Has/does happen frequently. I have seen sharks continue to grow until then cannot turn in their tank - that is when the owner usually calls a public aquarium.> Your websites opinion on the matter, it would seem, differs from that of the biologists. I would be interested to hear your response. <Well, you have mine. Likely others might feel differently here at WetWebMedia, and this posting might inspire more opinions, scientific findings etc. from our readers at large. Thanks for the question ~Paul>   Sincerely, M. Dare

Questions on Pheromones Dear Mr. Fenner, <Steven Pro this morning.> I read your article on growth inhibiting substances and I found it very interesting. You mentioned boiling water, aging water, skimming, activated carbon, partial water changes as possible ways of removing or at least reducing the pheromone content of the water. Anyways, I'm going to be creating a small hatchery for various cichlids in the near future, and I was wondering if there are any other ways to remove the pheromones within an aquarium? For example, are there any chemicals that could effectively destroy the pheromones of the water? <The best thing you can do for raising up baby fish is frequent water changes.> Thanks a lot! Steve <You are welcome. -Steven Pro>

Fish growth and tank size Hi guys, I need to solve a question that has been coming up a lot lately on many of the fish forums. Do fish only grow to the size of the aquarium they are in? I think this is an idiotic statement, but I've been an idiot before when it comes to this hobby. If fish only grow to the size of tank they are kept in, why did I have to upgrade from a 75g to a 125g tank when my Koran angel outgrew the original tank? I didn't see any indication that he was going to stop growing anytime soon. :) Thanks and great job on this web sight. I've been coming here for 2 years and it only gets better!! Regards, Susan <Susan, the idea that fish will only grow to the size of their aquarium is an old one, but is only slightly true. Freshwater fish are fairly easy to stunt and usually do not outgrow their tanks. They just usually die prematurely from health complications from poor water quality in cramped quarters or they just jump out and die on your rug. Saltwater fish do not stunt well and again succumb to the health issues relating to water quality or jump. In general, if you want a healthy, happy pet, provide it with plenty of room, good overall water quality, and a varied diet, and you will be rewarded with a long-lived friend. -Steven Pro>

Tank size After a disastrous foray into the hobby years ago I have decided to  return. this time armed with extensive research (really appreciated your  book) and a patience I didn't have before. In reading all these books,  articles, and comments by hobbyists I can' t seem to find a clear cut answer  to the question: what will happen if I put a juvenile Queen Angel into a 100  g tank (in planning stage at this time). Will it eventually outgrow the  tank?...or will it grow only to a certain size given the confines of the  tank. I love these fish (some kind of dreamy psychic connection) but can only  afford space wise, a 100 g. Would I have to eventually give it up? (Can't  bear the thought and I don't even have it yet) What would you do? Thanking you in advance Ian Tucker >> Good writing... A Queen Angel (Holacanthus ciliaris) would just about fill up a one hundred gallon system... and will/would take years to get really too big... I would not place (of course) any other marine angels... but you could place some equally quixotic and beautiful tropical west Atlantic species... maybe a Queen Trigger, a Hogfish... This question of "the size of a system" determining/limiting growth, "happiness" of livestock is near and important... Many variables at play... metabolite build up and negative feed back, social dynamics, the effects of light, temperature... I have a couple of articles titled "Optimizing Growth" and "Growth Limiting Factors" stored at www.wetwebmedia.com you might enjoy reading over.... Bob Fenner