While on the subject, the myth of fish only growing to the size of a tank.
Is it the actually square footage?
In a way yes, but no.
Because in a small tank the water goes bad very fast, so the reality is, a fish will cease to grow if conditions are bad.
But what about good filtration?
Filtration holds particulate, and the benificial bacteria that use ammonia and nitrate.
What filters don't do, is remove those growth chemical and organic substances like hormones, and nitrate, that only water changes do.
So to me, most filtration is a smoke screen, there to make the viewer happy, not the fish.
In nature the fish are invisible due to turbidity and particulate, look at the Mississippi and try to see the fish, yet they are there, living quite well, and growing to massive sizes.