I have 2 in my 8 gallon nano that I have at work. I started with 4 but now down to two, and one lives in the back chamber of my tank for whatever reason and is huge now so it's getting food somehow. I don't supplement them with any other foods at all and they seem to be doing great. Don't seem to bother my corals at all. They say 3-6 is a good starter pair but I haven't been able to find any new ones to add to my tank. But they are awesome. I've also got a Harlequin Shrimp, candy cane pistol shrimp, Anemone Shrimp, and a Porcelain Crab in the tank and they all get along great.