They are so fun to have. I used to have a group of 4 but now only one in my tank. As they grow older, it's good just to have single. They eat like pig and mine doesn't bother any fish or corals at all. Mine does move sand alot though. Just moving the sand, not swifting it. Mine is around 5 inches now and it actually response to you. When I come and tap on the tank...it comes out and hang out where I am at. It used to be buddy buddy with my watchman goby but now they have move on to diff spot of the tank now.