PersonalI would do more bichirs check out some of the uper jaws like endlis the problem with a catfish with rays is usually the catfish eats all the food and the rays and bichirs don get as much as they need
Bichirs are great fish some of the wild caught upper jaws can hit the 30inch mark and eat everything and will not bother the other fish
just maybe only 1-2 because it is already pretty heavily stocked