My bumbleebees are in fresh water. According to a gobiologist (fish scientist) friend of mine, there's a lot of misunderstanding about these fish. For one thing,
Hypogymnogobius xanthozona doesn't exist in the trade. They are exceptionally rare in the wild (apparently most museums don't even have them). So forget about that name, or its synonym,
Brachygobius xanthozona. Any references to that fish in the books are wrong.
The ones that are traded include
Brachygobius sabanus and
Brachygobius doriae. Identifying any of them to species level is something gobiologists do with dead specimens because you need to count fin rays, rows of scales, and things like that to be certain. Essentially impossible to tell apart in aquaria regardless of the photographs you see in books (which are often, I am assured, wrong).
Anyway, the commonly traded ones do equally well in fresh or very slightly brackish water. Salt is NOT essential, though some aquarists have found it helps for them. I don't use salt, and my bumblebees are big and very, very fat. The water in my tank is hard and alkaline, and the gobies coexist with other gobies, a South American puffer, halfbeaks, and a few other peaceful fish. The important thing is that they get some food.
Mine love (and I mean LOVE) shrimp eggs scraped from the bellies of coldwater prawns. They will eat these until the explode. Lobster eggs, which you can by as food for marine fish at your tropical fish store, make a reasonable substitute. My gobies will eat some bloodworms, but aren't wild about small crustaceans like mysids or brine shrimp. They do like tiny pieces of cooked prawn, so I keep a bag of these in the freezer at all times.
These fish like hiding places, so I use lots of plants and leave some of the dead leaves in the tank just for them.
Check out Frank Schäfer's AQUAlog book on Brackish Water Fishes if you can. It has an excellent chapter on gobies.
Cheers,
Neale
Here's one female of whatever species I have...
