Bumble bee gobys are great little fish, They are brackish water fish (but some people kept them in freshwater). I feed them bloodworms, whiteworms, brine shrimp and daphnia, mine dont like flake food.
A tank with lots of rocks and plants is a good idea so individuals can establish territories, sometimes they fight over food (very funny to see 2 bumblebee's play tagawar with a worm)
If you want to try breeding them (not very easy) put 6 or more in a tank with the salinity around 1.010-1.015 wait about a week then add freshwater (lowering the salinity sometimes triggers spawning). When ready to breed the females will have a fuller body and the males black bars may fad.