I have three. All live happy together in a seperate part of my tank. They have eaten a goby and a filefish so far.. Definitely not to be kept with any slow moving fish. Few expensive dinners before I learned my lesson. I was lucky enough to put a mesh devide up to keep other fish from entering their space. We had a tank custom built with a glass divide that had a 6 inch hole cut in the center so we could cap off one side of needed to quarantine sick fish or put mesh to allow the water to flow yet keep things seperate. Its worked a treat! I plan to get a few more. Having a tube only tank. They are gorgeous and live happily together!