Welcome to the forum, biksz.
It's true that fish often don't outgrow their tanks, but only because they get stunted, suffer from deformities and diseases and die very young![]()
What are the dimensions of your tank and what fish do you have?
I think he meant that the fish will grow to their full size without becoming stunted as they are in a big enough tank, thats what i got out of it anyway![]()
Welcome to the forum![]()