Whe i started this hobby four years ago, i unknowingly purchased one form my lfs, and threw him in my tank after it had been set up for a couple months. The poor little guy starved to death. After waiting about a year or two, i tried another one, and he has been doing well ever since. For some reason, my lfs likes to stock these guys, and 3everyone they get in seems to be malnourished. If you are going to purchase one, make sure that they're body cavity is full and cylindricial without any depressions anywhere, and youll have a better chance of enjoying this cool little fish. By the way, with a DSB you can keep a number of other cool gobies, such as a pair of twinspots. THese guys are really cool cause they may dig a couple holes under rocks, but constatnly sift the sand, searching for food. They are great little fish with wonderful personalitites, but just remember to purchase a pair, as singles often have shorter lifespans
JMHO, Good luck, Jon