Mystus Bimaculatus

[AMS]

My LFS luckily has a wide range of rare species often for sale, including many brackish species. They really know their brackish fish inside and out. But one thing has me confused, they have 5 Mystus bimaculatus species in their display tank, but it's brackish! I am almost 100% sure they are not Horabagrus brachysoma, they have the infamous two spots, and look like the other Mystus bimaculatus Ive seen. I am guessing that the tank is low-end brackish as there are low brackish tolerant plants, figure 8's, dalmation mollies, knight gobies, and glass-fish in the display tank as well. The owner says the are found inland, but unknown to many people's knowledge there are some specimens that live in the brackish waters of the Indonesian islands. I asked him if he was confusing them with Gunther's sun catfish (Horabagrus brachysoma), he said he is not and is sure they are M.bimaculatus.

I have never heard of them being brackish, googled it, and still havent found any info on them about being brackish. Are they actually brackish?? They didnt look stressed at all, but could it just be because they are hardy?

 

[nmonks]

There are lots of bagrid catfish that inhabit slightly brackish water, just as there are numerous ictalurid and siluriid catfish in brackish water. The idea catfish are somehow "allergic" to brackish water because they don't have scales is a total myth. Catfish are in fact very common in slightly brackish habitats, even ones not otherwise seemingly adapted to them. There are lots of plecs in the slightly brackish waters of Florida, for example.

But to answer your question, the only species that I know of that is a specialist inhabitant of brackish water is Mystus gulio, which can be kept at anything up to ~1.010 SG. It doesn't seem to be traded as an aquarium fish, which is a shame, as it looks rather nice.

I'm pretty sure that Mystus bimaculatus is normally a freshwater fish, and so while it may tolerate brackish water I doubt there is any advantage to keeping them thus. Either way, I'd definitely keep them at SG 1.005 or less.

Cheers,

Neale

 

[AMS]

Such in depth responses, thanks Neale!