Fish Getting Stunted In Aquarium

[fry_lover]

Doing some research on the issue, we often hear about the risk of stunting but i never see much scientific information on it,

I know its a not a completely black & white subject with a magic forumula, but there must be some general rules and principles

Dont worry, i am not trying to work out how long i can have a Arrowana in a 100 Gallon or anything like that, i just would like to know a little more about it, the less vague the better

Anyone got any articles or good links that really goes into it?

PS: looking for a bit more than "its when fish have too small a tank and they stop growing"

 

[afishdude]

well its when fish have too small a tank and they stop growing.

lol

anywase did you try the scientific section?

 

[rdd1952]

From what I have read, stunting is more a function of bad water than anything else. Check this thread that I started a while back about what causes stunting.

 

[fry_lover]

was thinking about it, but i think the idea of that forum (Scientific) is to actually bring some info INTO it and start a debate, i am starting from scratch, thats what i am looking for, some scientific info, not just the biology of what happens (i am aware internal organs carry on growing, but fish doesnt on outside), but ALSO, some general guides on where you draw the line so to speak and how to reduce the risk (see below for obviousl methods to reduce risk!)

It makes me sound like i am trying to push the limits of fish keeping, but its really for personal fish-keeping development.

Just want to learn something new also, apart from "big fish in small tank" and "build up of waste" i know very little about it, especially with regards to advising others on stocking levels (and the risk of stunting), and as i am someone who generally pushes it with stocking levels i want to know a lot more about stunting.

Obviously the easiest and most effective method to ensure no stunting is low stocking levels or conservative levels, but i want to supplement this with some more facts if you get my drift

 

[fry_lover]

From what I have read, stunting is more a function of bad water than anything else. Check this thread that I started a while back about what causes stunting.

Brilliant Rdd, just what i was looking for (i had actually found one of those articles while on Google earlier, the one about the mass of the Oscar)

So really, it looks like its more a question of water quality than space (the two often but dont neccessarily go hand in hand)

So like many other issues associated with "over stocking" there are quite a few factors to consider before we start saying "that fish will get stunted", obvious exceptions will apply, like a Pacu growing in a small tank, i was also wondering what other general "rules" or actually "best guesses" people would agree on about stocking levels, size of fish, size of tank in relation to stunting.

EDIT:

the hormone issue particularly intrigues me and makes a lot of sense, i always understood it to be the reason for doing daily water changes (along with a good diet) to speed up the growth of fry.

Do you think there's any suggestion or evidence that plants take up some of these hormones?

 

[Bignose]

I haven't researched this much, but one of the myths that always seem to come up is the "the organs keep growing but the skeleton doesn't" nonsense. I have asked for proof of this for several years, never ever to find any. There have been some gruesome examples of stunting, including deformed fish, but usually it is something like an oscar in a 5 gallon tank that literally didn't have room to move.

I will ask again, if anyone has any proof of the bulging organ myth, I'd really truly like to see it. Not friend of a friend knows a guy, not internet hearsay, actual honest to goodness firsthand knowledge.

I wrote up a long post quite some time back now why nature in all likelihood would NOT create bulging organs in response to a growth-limiting environment, it would just slow the growth the the entire fish, skeleton and organs alike.

 

[cuticom]

I've got a few stunted goldfish here, and apart from having eyes way way to big for their bodies, and huge fins, they look fairly normal, they act normal as well, ones 8 years old, if the organs were gonna grow without the skeleton growing, I woulda thought he'd be a touch more deformed by now.

From what I've experienced, I believe stunting is caused by a growth inhibiting hormone released into the water, as that makes sense, after all mother nature would have some sort of defense mechanism if the fish ended up in a puddle (ie Bettas being able to breathe air)

 

[ronanphilip]

seen this a while back click

 

[fry_lover]

good link, ,thanks

 

[rdd1952]

So really, it looks like its more a question of water quality than space (the two often but dont neccessarily go hand in hand)

If the hormone issue is true and I feel sure that it probably is, I think they actually are very much connected. The hormones given off by an oscar for example, will drive that level much higher in a 5 gallon tank than in a 30 gallon tank. So even if you do weekly 25% water changes in both, the hormones in the small tank will be much higher and result in very little growth.

 

[fry_lover]

So really, it looks like its more a question of water quality than space (the two often but dont neccessarily go hand in hand)

If the hormone issue is true and I feel sure that it probably is, I think they actually are very much connected. The hormones given off by an oscar for example, will drive that level much higher in a 5 gallon tank than in a 30 gallon tank. So even if you do weekly 25% water changes in both, the hormones in the small tank will be much higher and result in very little growth.

my point was, just because a tank is bigger, doesnt mean the water quality is better (can't be assumed anyway), and if its the hormones we talking about then the same stands true, just because the tank is bigger with same size fish as a smaller tank, doesnt mean LESS hormones in the bigger tank. Will depend on water changes (thats my focus), hence my post of "doesnt neccessarily" go hand in hand but "often" does

EDIT: i.e

Tank 1 (300 litres) has x1 10" Oscar in it, gets a 10% water change a week

Tank 2 (200 litres) has x1 10" Oscar in it, gets a 25% water change daily

Tank 2 is smaller but has better water quality based on above stats (if all else equal)

 

[rdd1952]

fry_lover I agree. What I was saying that if you make equal water changes, the hormones would be higher in the smaller tank since the fish are going to put the same amount of hormones in both tanks.

 

[Bignose]

I've got a few stunted goldfish here, and apart from having eyes way way to big for their bodies, and huge fins, they look fairly normal, they act normal as well, ones 8 years old, if the organs were gonna grow without the skeleton growing, I woulda thought he'd be a touch more deformed by now.

Please don't take this as me picking on you, but even this is sketchy evidence. The eyes could be too big for a whole host of reasons, not the least that some goldfish are bred to have large eyes and yours may just have a little of those genes somewhere back in their history.

To really answer this kind of question, a study with a control would have to be performed, but even the lack of anecdotal evidence makes the bulging organs idea very unlikely.

fry_lover, here http/www.fishforums.net/index.php?showtopic=93933 is the old thread I started on this, there are citations to some relevant scientific journal articles there. Also, noone had any evidence of bulging organs.

 

[Tolak]

I know that oversize eyes is a sign of stunting in angels & discus. Eye count, or how many eyes tall a discus is above & below the eyes, is an important thing to people breeding & showing discus. I have no idea if this applies to goldfish, but it does to many cichlids.

 

[Tokis-Phoenix]

I think stunted growth depends on the exact type of fish in question, some fish seem more prone to it than others, and for different reasons too.

I know that with red tailed catfish, their growth is very difficult to stunt if you keep them in good water quality conditions and on a good diet, they will just keep on growing and growing, even if they can't physically turn around in the tank.


Bad or less than desireable water quality can stunt the growth of many types of fish, but the water quality does not always need to be "bad" to stunt a fishes growth- i know that with clown loaches for example, even if there are no nitrites or ammonia in the tank, if regular water changes are not done then this will stunt the growth of the clown loach.
I'm not sure exactly why this happens with clown loaches, athough i suspect it has something to do with the mineral build up in the tank from lack of water changes- in the wild, many fish which live in waters whose conditions change dramicatically at various points in the year, like during a dry season and wet season. Many types of fish stop growing as much as the dry season progresses- I think they detect the build up minerals in the water that naturally come about as a dry season progresses, and this triggers the growth in the fish to slow down, since this would have many benefets during a dry season where there isn't much food and space to swim around in as the lakes and rivers start to dry up.

So not doing enough water changes may trigger the fishes dry season survival response, and the fishes stunts its growth- doing lots of water changes would make the fish think its living in a plentiful wet season, and so it continues to grow at a normal healthy rate etc.


I think people should always give fish a decent sized tank and habitat though regardless of stunted growth issues, because of welfare/welbeing issues of the fish concerned. Because water quality conditions also seem to play a large part in many cases of fishes stunted growth, it is also very important to do regular water changes, to keep the water quality good and prevent excessive mineral buildup and to also reduce background levels of any diseases/parasites lurking in the water etc .


Another very basic cause of stunted growth in fish, although mostly seen in the larger growing fish, is people simply not feeding their fish the right foods or enough of them- i have seen so many tankbusting or large growing fish like common and sailfin plecos, bala irredescent sharks and oscars etc that have not grown as large as they should because they were not fed a good diet.
I have to admit myself that in the early days of my fishkeeping hobby when i did not know as much as i curently do, i probably didn't feed my plecos as much food as i should have fed them (of course now days i do).