Which smaller fish for a brackish community?
I’d like to try my hand at a brackish community set-up as those kinds of habitat have always fascinated me. But I only have space for a 60cm tank which limits my options as it rules out a lot of the larger fish such as Scats and Monos. What kind of brackish fish could I fit into a tank this size that would mix together? And what salinity is best?
SALLYANNE, VIA EMAIL
NEALE REPLIES: While there are some exceptions, the bigger brackish water species tend to be the migratory sorts that move in and out of rivers, often spending some part of their lives in the sea. Scats and Monos make wonderful aquarium residents, but do demand a lot of space.
There are many smaller species of fish that inhabit creeks and streams that are mostly freshwater habitats in many ways, but being exposed to periodic, although slight, changes in salinity. I like to think of these as ‘low-end’ brackish water habitats, and these are the realms of such things as gobies, sleepers, livebearers, and killifish. To keep these fish well, all they really need is a taste of salt in the tank, something like a specific gravity of 1.002–1.003 at 25˚C.
Some of my personal favourites among the less familiar livebearers include the beautifully coloured little livebearer Micropoecilia picta; the Wrestling halfbeak, Dermogenys
pusilla; and various Limia species such as the very hardy Humpback limia, L. nigrofasciata.
Among the more regularly traded gobies, there are several Brachygobius species known somewhat loosely as bumblebee gobies. But there are some alternatives, like the Rhino horn goby,
Redigobius balteatus, and the Desert goby, Chlamydogobius eremius, which is well worth looking out for. The latter
is real favourite of mine, among the easiest gobies to feed and breed, but short-lived, so you will need to set up a breeding colony if you want them in the long term.
While there are many brackish water killifish species, relatively few are traded. The most obvious is the widely sold Striped panchax, Aplocheilus lineatus, an Asian species that gets to about 10cm in length — artificial forms like the Golden wonder killifish have been traded for years — but it has a surprisingly large mouth, easily able to swallow up any small fish that gets too close!
The Florida flagfish, Jordanella floridae, is another small killifish that does well in low-end brackish systems. It’s a good community resident up to a point, being small and colourful, but the males are territorial. It’s sometimes been described as ‘dwarf cichlid-like’ in behaviour, and I think that comparison is fair.