Just lots of sand for them. Some people don't like them, say they deplete the sand of life, but I have never had that problem in my tanks. In a 46g I wouldn't keep more than one. They like to dig so make sure your rock work is sound or they may topple it. Also gobies are known to try jumping from the tank, so you may want to keep the tank covered. I have tried 3 or 4 diamonds and all ended up on the floor within a week. I have had a pair of brown bars for about two years now with no problems. Their only down fall is that when they dig or sift they tend to carry the sand higher in the water column. They haven't damaged any coral yet and they are busy little suckers. They have also taken to prepared foods from the get go so I know they won't go hungery. They will eat mysis, flake, nori and once in a while brine shrimp.