Very few rainbows are brackish, and the ones you find in a lfs are almost certainly purely freshwater strains. The only rainbows that I know for certain are truly brackish fish are Pseudomugil cyanodorsalis but they are hard to find and very small fish that would probably end up as lunch. Some will tell you that bosemani or neon rainbowfish are brackish fish, but it isn't true.
I don't know much about Celebes rainbowfish, they're more distantly related to the Australian/PNG rainbows, but I believe that they are freshwater inhabitants as well, so I wouldn't assume that they should be put into a brackish tank. A couple of rainbowfish species have been found in brackish water (NOT bosemanis or praecox if you were wondering). This led to some people to assume that all rainbowfish species (spanning at least 7 genera, and probably well over a hundred different species) can be kept in brackish conditions. This assumption has been spread by word of mouth and over the internet to the point that some accept it as truth with no firsthand experience or knowledge of the natural habitats of these fish. The truth of the matter is that only the few rainbowfish species found in brackish waters in the wild are really suited for such high salt concentrations and while other species may not be immediately killed by the high salt, it does reduce their lifespan and can compromise their health.
my LFS, which is the best in the state, keeps their celebes rainbows in brackish water and all the avalible stuff i've been able to see on them says that they are indeed brackish water. however... you are the rainbowfish expert, and im not.
my LFS, which is the best in the state, keeps their celebes rainbows in brackish water and all the avalible stuff i've been able to see on them says that they are indeed brackish water. however... you are the rainbowfish expert, and im not.
I don't really know much about the Celebes rainbows, they may in fact be brackish fish (like I said before, they are more distantly related to the Australian/PNG rainbows which are the only ones I have experience with). I would just make sure that they do indeed come from brackish water or semi-brackish freshwater before I put them in a brackish tank. I've just seen too many instances where people generalize and say that "rainbows can be put in a brackish tank" and then recommend neon or bosemani rainbows which are strictly freshwater species.
