I started a thread a while ago called
Brackish water fish that aren't, and bumblebee gobies are a case in point. According to the scientific literature, as well as the
Aqualog book on brackish water, and from my discussions with a professional gobiologist, the bottom line is this:
Bumblebee gobies naturally inhabit fresh, rather than brackish, water.
Many, like
Brachygobius doriae, are even found in soft, acidic conditions similar to those discus and neons thrive in! The idea that bumblebee gobies
need salt is a myth, and probably more about the fact people look after them badly. They don't eat flake food, for example, and they cannot compete for food with active species. So, I'm sure the majority of bumblebee gobies die because they starve to death.
The second question is does adding salt help. According to lots of people who keep them, and even according to the Aqualog book, adding salt does make for healthier gobies, particularly if you want to breed them.
My own bumblebee gobies are in an aquarium at pH 6.5-7, with peat filtration and only moderately hard water. They seem to be doing fine, and have been for the last 9 months, with the females ripening with eggs and the male at least once donning spawning colours. I had a pH crash a month or so ago when I lost some fish, but the bumblebee gobies weren't among them, so they seemed to tolerate a pH of less than 6 for at least a day or so.
A problem with the aquarium books is that (I am very reliably informed) almost all of the pictures are misidentified. For example,
Hypogymnogobius xanthozona simply doesn't get traded because it is incredibly rare in the wild, so any book or magazine that refers to "
Brachygobius xanthozona" is unreliable. The commonly traded species (in the UK anyway) are
Brachygobius sabanus and
Brachygobius doriae.
Bottom line, bumblebee gobies are not "brackish water fish" in the sense of naturally coming from brackish water habitats. They can adapt to brackish water, and there is some evidence they are easier to look after in brackish water. Some will adapt to sea water as well, if it's done carefully (but then, so will some cichlids, but no-one recommends keeping them in reef tanks!). On the other hand, they can be kept in freshwater indefinitely, all else being equal.
Cheers,
Neale
PS. The
Brackish FAQ has links to the Fishbase pages for the most commonly traded species.
