I have been waiting for a chance to ask this question - do fish grow in relation to size of available space?? Long ago, like 40 years, I was told this and my kids who always had aquariums with various fish that I am now being told will get too big for the size aquarium I have, Yet we had a clown loach, kuli loach, algae eater, and various catfish for years without fatalities in a 50 gallon tank - amongst the other fish they chose. The only thing that didn't work out were the ciclids and the oscars. I am not saying we had several of each, but I remember we had at least one of the first four I mentioned that were there the entire grade school and high school years.