My experience with my Yarelli that is 12" now is not a very active fish. I would say its a peaceful fish that is never shown me any aggression toward any fish. It sits in one place most of the time 24/7. Only swims when the tank is pitch dark but even then it doesn't swim that much. He eats only live feeders when one swims close to its mouth and only when its hungry.I keep lots of feeders in the tank so he eats them when ever he wants to. I kept him with my Goliath tiger when he was only 5". The tiger is now about 9". I also keep a school of Widebar dollars with my goonch. My goonch actually got picked on by my dollars when I first put him in with them. Got his tail and pictorial fins chewed on. I almost separated him but left him in there and now the dollars leave him alone. I say you can keep most any fish with him as long as there at least halve the goonches length. And they don't spend all there time on the bottom where he's at. Oh and the tank is 100 gallons.
i got ideas for the future....