Do fish reach their full length even if in a small tank?

[Charlottie]

I have just had this talk and i thought maybe somepeople on here would know better than me as im not all clued up on fish!

I was thinking that they would still grow to normal size no matter what the tank size was ?
OR
Like my mums bf pointed do the fish know how much they can grow till they are the right size for the tank they are in and then will it somehow prevent its self from growing ..

If he is right how do they stop them selves from growing to their full potential (sp) ?

Thanks for reading
Charlottie =)

[Trillian]

If a fish is in a tank that is too small for it, it switches off its growing gene, thus ending up stunted. This obviously affects its health and significantly shortens its lifespan. The LFS people euphemistically call it "growing to the size of the tank" which sounds like an acceptable compromise but isn't IMO for the reasons outlined above.

Case in point - the much abused goldfish which has the potential to grow to between 6-12" depending on the species and can live up to 25 years, if properly housed and cared for. But if kept in a small bowl or tank, will only reach about half that size and lifespan, if it's lucky.

[Marine]

Thought it worth mentioning that this doesnt apply to marine fish.

An atlantic blue tang for instance that you can buy from around 2" upwards in your local shop will grow to a good 13" over time no matter what size tank you put him in.

You will of course end up with one very stressed / aggressive fish at some point when he gets too big for the tank and there are very few home tanks that can house a 13" fish happily.

The number of fish like these you see in shops must mean that they die regularly in home tanks otherwise there'd be a lot of large fish looking for new homes

[TUBBS]

one thing on the stunting, its only the bones that stop growing, the organs carry on and thats what harms the fish worst of all, they will always grow too big for a tank befire stunting comes in though

[Esfa]

Not all fish stunt too, some just keep on growing!

[khaostim666]

hmm this just gave me an idea, i havnt had fish in ages!, pay day im off to buy some!!! Wooooooo

[strictly_scales]

No... they will end up stunted and deformed. Fish keeping is simple- if you cannot afford/ have a tank large enough for the species you wish to keep, you can't have it... I would love a Dovi, an Electric Eel, a Bamboo Shark, an African Lungfish, a Shoal of Silver Sharks etc, but I live in a first floor flat and cannot have a particularly large tank...

There are so many amazing smaller fish that you really won't be suffering.

[xyra]

stunting is often caused when the water gets polluted from the larger fish (small tank volumes and filter capabilities are aimed towards small fish) so it isn't healthy enough to grow new bone. the internal organs continue to grow as has already been said and you end up with a heavily deformed fish.

99.99% of the time if the water in a tiny tank is kept perfect (say with daily water changes and big filtration) then the fish will keep growing and growing.

THere is a belief although I don't know if its been backed up with any studies that some species (specifically some SA cichlids) give off a stunting pheromone so other fish in the area in the wild don't grow as fast giving the fish an advantage. In an aquarium this may rebound and effect the fish emitting it. However I have always read this as speculation - if any one knows of any actual research being done let me know

But in answer to your question. In good conditions fish don't stop growing in small tanks as a rule.

[TUBBS]

nah it's not been proved yet, i dont know why the big companys haven't done it yet as they have the lab conditions to do it in which they do food trials in, maybe aquarian would do it at the waltham centre of research as that lab publishes everything it finds even though aquarian pay them to do the trials

[Charlottie]

Thank you very much for the replys!

x