Part of the problem is that the fishkeeping trade doesn't distinguish between the species, and the aquarium books use the wrong names.
Hypogymnogobius xanthozona (=
Brachygobius xanthozona), for example, is often seen in books but is, I am reliably informed, so rare even most museum collections don't even have preserved specimens.
The common species are
Brachygobius sabanus,
Brachygobius nunus, and
Brachygobius doriae (listed in no particular order). Other species may turn up as well. For the most part, trying to identify bumblebee gobies to species level is beyond the ability of the home aquarist (you need to count scales, which means putting a dead specimen under a microscope). I'm told by a scientist working on gobies that virtually every photograph published in the aquarium literature (books and magazines) is wrong. A scary thought...
Anyway, in the Aqualog "Brackish Water Fishes" book, probably the most reliable book on the topic, the author goes to great lengths to explain that bumblebee gobies, halfbeaks, and glassfish aren't brackish water fish whatever the hobby may think. I think he over-eggs the pudding a little here... while there's no question that while these fish might not naturally occur in brackish water habitats, they
do seem to do well in brackish water aquaria.
Personally, I keep my bumblebees in a tank containing slightly acidic, moderately hard water filtered through peat. They are as fat as fancy goldfish and seem to be healthy, and have been for months. On the other hand, I've read reports of people breeding them in something approaching full strength sea water.
My gut feeling is that other factors are more important, in particular feeding. These gobies are notoriously finicky, and it took me a while to find something they'd eat with enthusiasm (shrimp and lobster eggs).
Brackish water may be helpful, but I don't think its essential, and these gobies certainly are known to live and breed in soft, acid water miles away from the sea. In the Aqualog book, for example, the author says that he has only ever caught them in fresh, not brackish, water. He does go on to say that 5-10 ppt strength sea water is best for breeding though (normal sea water is about 35 ppt, by the way).
Cheers,
Neale
The-Wolf said:
Can someone show me positive proof of a freshwater bumblebee goby AFAIK all brachygobius species are brackish.