What fish can I keep with Firemouths?


Neale Monks advises one of our readers on the best way to get moderately aggressive cichlids to tolerate tankmates...

 Q)I’m setting up an aquarium as a biotope for Firemouths. I wondered what fish you might recommend for the upper levels — I'm thinking livebearers, but what would be best? Should I add these other fish before the Firemouths?


A) NEALE SAYS: Certainly, the best way to get moderately aggressive cichlids to tolerate tankmates is to introduce the cichlids — as juveniles — to a tank where the midwater dither fish are already well established. That way, as the cichlids grow, they will (hopefully) treat the livebearers as part of the background scenery, rather than trespassing rivals or food.

Indeed, healthy, lively dither fish can encourage territorial cichlids to behave in a more normal way. In the wild, bottom-dwelling cichlids know they’re at risk from terrestrial predators like fish-eating birds. While they can’t see those sorts of predators, they know that surface-dwelling fish can, and so watch the behaviour of such fish. If minnows or whatever are swimming about in the open, rather than hiding or darting about in a panicked manner, the cichlids will deduce that the risk of predation must be low. This encourages them to leave their hiding places and forage for food in the more exposed parts of their environment.

So, on paper at least, choosing the right dither fish for your Firemouth cichlids will do a lot of good. Your cichlids will swim about more confidently, showing off their brightest colours, and they’re also more likely to have a nibble at whatever foods you offer your dither fish. Firemouth cichlids are adapted to sift sand for insect larvae and other ‘wormy’ foods, as well as edible organic detritus of all sorts. But if they see other fish eating flake, they’ll likely consume that sort of food as well. While frozen bloodworms and brine shrimps make good staples (and fine treats) for Firemouths, flake and pellet foods often present a much more balanced array of nutrients, including vitamins and minerals.

Livebearers are good choices here because most species appreciate the same moderately hard, slightly basic water your Firemouth cichlids will want. Swordtails are the classic choice, though these are very active fish and can be quite feisty, especially the males. I’d keep either a single male or at least three, and in either case, ensure these were outnumbered by females.

You might also consider Mollies, though these vary in their hardiness, and when kept in strictly freshwater conditions can be a bit delicate — for whatever reason, Mollies seem to be less disease-prone in slightly brackish water, even though they are widely found in freshwater habitats across Central America. So, if you do choose Mollies, ensure water chemistry is stable and water quality excellent, particularly with regard to nitrate — like cichlids, Mollies do best when nitrate is kept below 20 mg/l.

Mexican characins would be good choices, but alas, very few are traded. Really, we only ever see the cave-dwelling morph of Astyanax mexicanus on a regular basis, whereas the surface-dwelling version, a silvery fish, would look rather good alongside the Firemouth cichlids. But you could stretch a point by using something that looks similar, and occupies a similar niche, such as the Giant danio. Easily obtained and very beautiful, these fish are fast-enough to avoid trouble while robust enough not to be threatened by the mere existence of the Firemouths.

Whatever dither fish you choose, it is important you give them the space needed to swim away from trouble. That means the tank should be no less than 120cm long, and ideally, you’d provide at least 40cm depth so that the cichlids and surface-dwelling dither fish rarely interact. Get the dither fish well established first, and once settled and growing well, introduce the juvenile Firemouths.

Do bear in mind that Firemouths breed readily in aquaria, and while they are fairly popular fish, the market for juveniles isn’t limitless. Your local retailer might happily take on a dozen every month or two, but not hundreds. If all else fails, just keep a singleton as part of the biotope, alongside your livebearers and perhaps a suitable catfish species.

Avoid a cichlid mix!

Resist the temptation to combine Firemouths with other cichlids. Firemouths are sand sifters, and their mouths and throats are specially modified to do this sort of foraging. As a result, the bones are delicate and easily dislocated, and while this isn’t usually a problem when two male Firemouth cichlids ‘wrestle’ over territory, it does mean they are easily damaged by other, more robustly built cichlids. This is the reason they have those eye-spots on their gill covers — so males can threaten one another before actually coming to blows. Such bluffs don’t work on other cichlids, and should the Firemouth get his jaws damaged, he’ll most likely starve to death. It’s a sad sight to see, but unfortunately, all too common when people make the mistake of keeping them with other cichlids.