I know people keep saying get a bigger tank for this or that, I was always under the impression that fish grew to their envirnment is this not true? I know dumb question but i've been wondering about that for some time now
Some fish are stunted by the tank they are kept in if it's too Small. I have seen Pacu and Oscars that were so big they couldn't turn around in their tanks. So If we take care of our fish as we should I guess the answer would be no they don't grow to accomadate their environment. We provide the environment they need so they can reach their normal size comfortabley and happily.
I think I read an article on this once...it said that while the size of the tank has nothing to do with a fish's growth, often in too small of a tank the nitrates will build up to the point where they actually stunt growth.