Armatus or an fire eel is one possibility too.Dude get an Armatus, you could totally keep one in there!
Im pretty sure that I couldnt find that black devil catfish from my country's pet shops. Same for the African pike.black devil catfish... ive read they top out about 28 inch is that right? surpossed to be great wet pets and really aggressive!.... i really like them!
clown loach would be cool maybe with a group of african pike odoe for the surface?