ok they have 2 redtail catfish at my lfs ..one is 4 inches and the other is like 3 inches...i have a 55 gallon but i was wondering how long could they be their before getting big...ps i might not get one but still wondering .thanks
Probably a few months before they get "big" which for you would be over 12" because of your tank width. Honestly not worth getting unless you have a upgrade coming for the 55g in a like a month or two.