Excerpted from: Five Almost Perfect Fishes; Great fish for the community aquarium, except for one little thing'¦ by Neale Monks   

5                     Bumblebee gobies, Brachygobius spp. 

The good:            A colourful character that does great in hard, alkaline water

The bad:              Live or frozen foods -- it won't eat flake! 

These delightful little gobies are among the nicest fish in the hobby. Good specimens have bright yellow bands set against a black background, and really grab your attention despite their size. They aren't all that active, but they are territorial, so while they don't need a huge amount of space you do need to make sure each fish has its own territory. The easiest way to do this is make sure there are plenty of shells or caves in the tank, and the gobies will do the rest. It's quite good fun to watch these fish go about their business: they might seem a bit sleepy, but they defend their homes with remarkable courage! They tend to ignore other fish, and for the most part other fish ignore them; some people have even suggested that their black-and-yellow colours are a warning that they taste bad or are poisonous. Even so, it wouldn't be wise to rely on this to keep them safe from substantially larger predatory fish. 

Anyway, with bumblebee gobies what you get is a peaceful, strikingly coloured little fish that will work nicely in any aquarium with hard water (and preferably a bit of salt added). Whether or not they are strictly speaking brackish water fish is a debateable point. All three of the species commonly sold in tropical fish stores are know to live and breed in completely fresh water, and there is variation within each species, with populations found in estuaries needing salt and the ones found further upstream doing fine in fresh water. Some populations inhabit soft, acidic waters like those favoured by many other Asian freshwater fish, while others can be adapted to live and breed in full-strength seawater! However, most of the bumblebee gobies traded commercially seem to do best in hard, alkaline water with a little salt added. 

Incidentally, the species sold are Brachygobius doriae, Brachygobius nunus, and Brachygobius sabanus. They are collected indiscriminately, so there's no reason to assume a single batch of fish contains just one species. Identifying the gobies you have to species level is extremely difficult; and for the aquarist it is probably pointless since all three require the same water conditions. Goby experts consider the only sure-fire way to name a bumblebee goby is to examine a dead specimen under a microscope -- something few aquarists are going to want to do. Moreover, almost all photographs published in books and on web sites are incorrectly named, so they aren't much help either. About the only certainty is that one species you won't have is Brachygobius xanthozona -- although the name is widely used in the hobby, this goby is so rare that most museums don't even have specimens of it, let alone tropical fish stores! 

Not that what your bumblebee gobies are actually called matters all that much, as the they all have much the same requirements as far as water conditions and feeding go. Which brings us to the prime flaw of these fine little fishes: they won't eat flake. Aquarists like their fish to eat flake and pellet food; for one thing it's inexpensive and convenient, but more importantly in the long run, good quality flake food is carefully prepared to ensure your fish get all the nutrition they need. However, bumblebee gobies just won't eat flake. They might have a bite, but they'll spit it out, and you'll definitely need to make other plans as far as feeding goes. Frozen foods such as bloodworms, lobster eggs, and mosquito larvae are probably the easiest option to take, though live foods are perhaps best. Even assuming your gobies will eat what you're offering, you need to make sure they get a chance to feed. In many community tanks the other fish will eat up all the food before the gobies get a mouthful, so if you want to mix bumblebees with other kinds of fish, choose fish that eat more slowly or ones that don't take food from the substrate (like halfbeaks).