The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
This is a myth with fish, people will say that a fish only grows to its tank size, while the outside of a fish may not grow the internals will and the fish may become deformed and ill...
But cories are not fish that will get stunted most of the time. It's more that the smaller the tank, the less room they have to swim. They're very active fish, so more room is better. A 20 gallon tank should let them swim around just fine.