I'll chime in on the Ctenopoma - I would not trust one with rainbowfish unless they are really big ones. I'm not sure how big the turqoise rainbows get, but they should be pretty good sized compared to the Ctenopoma or they will get eaten. My "Leafy" ate all my tetras when he was only about 2.5-3 inches. I never would have believed he could have even fit them in his mouth. Awesome fish though! They definitely lurk a lot, and mine is usually found in one of his hideouts just watching and waiting.