They are wonderful and do best in a species only tank and can do well in a peaceful BW tank.
When I had 6 in the QT
tank, I supplied them with marine shells and they defended them. Since adding them to the 29 gal
brackish community tank (3 flounders and 6 Celebes Rainbows), they ignore their shells and have taken up residence in various areas of the tank. They are slow eaters. I had 4 Mollies in there, hoping for fry so the bb gobies would have live food, but the Mollies ate everything in site, leaving nothing for the gobies or flounders. The Celebes are great since they don't go to the bottom of the tank to eat and add a flash of color. The gobies have the entire middle and lower part of the tank.