You could probably keep a tire track (my personal favorite) in there with a ck and jd. That would be very rewarding imo. You could also get a couple of decent sized G Tiles. Maybe you could do a larger peacock eel but I'd be careful because the ck will get big enough to kill it eventually. I would stay away from things like zig zags, etc with those tankmates. But my ck and tire track used to get along just fine....until the tt got out of the tank and died. So that's what you have to think about there. Eels are cheap and great but you need to secure your tank because they do get into trouble sometimes.