fish size question

I have heard from different people over the years that a fish will only grow as big as his environment will allow. Is their any truth to this? I have seen the same fish for example 1 being in a smaller tank only get so big and the same type of fish in a bigger tank be 2-3 times the size with the fishs age being pretty much the same. Now grant it these were freshwater fish (probably doesnt matter) and I understand each environment was probably different. Have any of you experienced fish keepers ever experienced this? Has any of you ever bought a small fish and it outgrow your tank? if so what kind of fish and how long did it take? I know this may be an "old wives tale" but felt it was worth asking the question.

 

I also had the same experiences with fresh water fish. I have seen lion fish kept in 20 gallon or smaller tanks that could barely turn around though.

 

I have also seen kinda the same thing but i dont know if the fish bought that size or did they grow to that size?

 

I have heard this applied to a great many animals - from fish and frogs to snakes and rabbits.

How big you will get is defined by genetics... and how quickly you will get there depends on your nutrition and competition. Less food available (hypothetically in a smaller tank) may slow that growth down, but it will not, can not completely stop it.


I think this comes from animals that die. They died bc, ultimately, they were in too small a tank, but the perception is that it died for other reasons but it never got a chance to grow up.



A fish has (exaggerating) infinite sized tank to grow up in when in the wild... yet they stay within their genetic definitions of size...

Anyway, IMO, hogwash.

 

I can't imagine someone bought a fish that poorly sized to it's tank. I am of the belief that there are probably some species that do not grow too big for there tank though. Just look at the size difference between captive and wild max sizes of most fish. They get much larger when there in the open ocean. It could be a predatory fish thing to outgrow. Only one way to find out unfortunately.

Bottom line is if a fish gets big it most likely wont be happy swimming in a small tank even if it does stay small.

 

Water conditions (generally speaking) are better in the ocean than in your tank (less swings and mini-cycles to deal with, more "natural" hunting and food gathering available...)

Basically, a fish has evolved to live off the available resources from where it comes from. Not to live in your tank. So I go back to my nutrition comment.

There is also the little factor of age. I haven't studied this greatly, but from a quick browsing of google, it seems to me that fish don't live as long in captivity. Fish aren't like humans in that they reach maturity and stop growing. They grow all their lives (albeit at slower rates after maturity).

 

The only exception I know of is fish from the Gold fish family. The secrete a hormone into the water, once it reaches a certain level they stop growing and breeding. This keeps them from getting to big, or having to many fish in there current environment. So they will adjust to the water volume there in. Found this out when I was reading up on the coy in my pond.

 

I believe this to be false information. For example, If you keep a goldfish in a 10 gallon aquarium, it will only get so big, but only because it dies before it can grow to be it's adult size. There's no way a goldfish can live in a 10 gallon tank for 10 years, but they will in a pond. So to a point, they only get so big in a small environment, but it's only because they die before they can grow to their adult size.

 

Very good point.

 

I believe they will outgrow your tank.. vlamingi tang is a good example.
I have seen a 2 footer in a home aquarium though. Of course the aquarium of the infamous david saxby.. which is HUUUGE!