A friend of mine has 2 piebalds. They're about 15 inches. Very aggressive and territorial around their hiding spots. They eat everything, not only small fish, and do most of their damage at night time. One is very active and the other not so much. They do go crazy at feeding time though! You could keep yours with an equally sized catfish, but do expect some fighting, at least initially.
SOOOOO jealous right now! That cat is on my dreamlist of catfish! and you have the calico piebald pretty pretty one!!!!