They will eat anything they can fit in their mouth, and if they start breeding they will run everything out of the tank. I had a pair in my 7 foot 210 gallon, and the took over 6 feet of the tank. They were in the tank with Fronts, Lepidiolamprologus Nkambe, Calvus, Compressiceps, and and around 10 other species. If you get a single specimen, you should be fine, but i wouldn't risk a pair in anything but the largest tanks.