I have 2 purples that I bought from a guy who was going back to freshwater. He had 3 but I did not buy the third because it always hid from the pair. So I suggest 1 or 2 if you can find a pair already together. They get along fine with my other fish(yellow tang, yellow tail damsel, cinnamon clown, 3 neon gobies, yellow watchman goby). Both use to go into the same cave that they had dug out at the base of a rock. They now hide in the rock work. As far as feeding mine eat live brine shrimp, flakes, frozen, and I have seen them pick at dried seaweed a couple of times. At first they hid alot but now after about 4 months they are out most of the time while the lights are on.