username

What's the minimum size tank that a full grown red tail catfish needs? Well I believe they grow 4 feet long but I don't know how big of a tank they need.

Butterfly

I wouldn't put them in anyhing smaller than a 500g tank maybe larger. They get about 4-1/2 feet and have a huge body mass. This is one of the fish that should never be sold to the general public. Most people don't have the tank or the knowledge to take care of it.
Carol