As stated they do grow large very fast but you do have quite a large tank. Maybe try a one that is about 2 inch long.
My brother has one housed with Angels, silver sharks, Gouramis etc and is pretty tame. The only fish it killed was one of his own and he did that in the first few hours. They do an ok job of cleaning up but not as good as the pure catfish.
If not the Red tail shark will be ok also, even both if you like