i saw these at the local fish store and they said 5 gallons would be fine . now, around here if something looks like a catfish we understand it to get HUGE. so whats up with them? they say they only get 6 inches, and if its true that theyll fit in a 5 gallon id like to get one for my 10 gallon. but im pretty dumb when it comes to catfish. any ideas?