Chaca chaca or Chaca bankensis( top of head spelling, sorry). They are more of a specialized predator though. Madtom Catfish, a small/barely medium size North American Native with 5-10 species in the genus(sometimes hard to acquire though, as well as Chaca, sorry). What about one of the smaller Pimelodus species from South America? Dwarf Giraffe Nose Catfish,there's a couple different species of those.of There are lots of sm/med catfish from Asia/SE Asia. Maybe a Synodontis species from Africa? Lots of colors/ patterns of those. They are relatively small,some anyway. Maybe a REDTAIL CATFISH ? You can get one of those at 2-3" and keep it about 3-4 weeks until it gets about 3' long!!! Lol!!! Sorry, off the actual point. One more, Many of the South American Woodcat genus have lots of meat species. More than 2000+ catfish species out there. Just start looking for some you like. Maybe you'll find one that you purchase and enjoy enough that you decide to invest in a larger tank size! If not there are PLENTY of smaller size catfish to make it a tough decision in the end on which species to go with! Good luck and enjoy yourself. Researching new fish that I am interested in is one of favorite things to do. Thanks.