Anything large enough to avoid being eaten that isn't aggressive will work fine. Tire track and/or fire eels make perfect tankmates for them, I have a 16" tire track with my 24" silver aro in my 220 gallon, and they get along fine. Some catfish will work, although just suggesting "catfish" as tankmates is not specific enough. There are many species that would make good tankmates for an aro, but there are also many that wouldn't. I would recommend that before going out and buying any of these fish, you do plenty of research on them and make sure you are able to care for them first.Tpriem21;4500944; said:I was also thinking about loaches... i like that idea. Does anyone second the catfish? Could i do cats and loaches? Thanks