I know the myth about fish only growing as big as their tank is a myth. When I worked in a petstore I have a hard time explaining that to people and having them believe me. I was approached many times by people wanting a ''cut little irredesent shark'' When I asked them what size tank they had, they usually told me anywhere from 5-55gallons. When I told them their tanks were to small for these fish they just said ''Oh, but they only get as big as their tank, so it's okay'' I told them that that was a myth and they will still grow but they with get deformed. Then some of them would say, ''but I have had fish that people told me would get big (usually the oscar as the example they used), I put it in a 10gallon and it didn't get that big or have deformations.'' What I was thinking in my head was I know your fish did have deformations but you probably didn't know it. But working at a petstore you can't say that to a customer.