• Species: Ameca splendens

  • Species: Brachyrhaphis roseni

  • Species: Girardinus metallicus

  • Species: Girardinus metallicus

  • Species: Heterandria formosa

  • Species: Limia perugiae

  • Species: Dermogenys pusilla

Rare Livebearers

30 March 2018


Livebearers are enduringly popular with aquarists, generally being small, lively fish that are easy to keep and breed. With a few exceptions, they are good community fish, and several species have become hobby staples, notably the farmed fancy Guppies, Mollies, Platies and Swordtails.

But there are dozens of other livebearers that make it into the trade periodically, and while they might not be quite so colourful as their fancy relatives. In this article we're going to look at some of these rarer livebearers, some of which are good choice for beginners, perhaps even better than the sometimes delicate fancy varieties of things like Guppies that have a bit of a reputation for being disease-prone at times. Others are more specialist fish, underling the point that despite their reputation as 'fish for beginners' the livebearers are really a much more diverse bunch than that statement would imply.

Dwarf Mosquitofish, Heterandria formosa

Sometimes called the Least Killifish in older aquarium books, this is the smallest livebearer, females reaching around 3 cm in length and males barely half that! Despite its small size, this little fish is actually quite hardy, doing perfectly well in unheated tanks and across a broad range of water chemistries, from slightly soft through to low-end brackish. Its size and adaptability makes it a superb choice for 'nano' tanks upwards of 25 litres, within which a group of 6-8 specimens could be kept without problems. Like other livebearers its omnivorous, doing well on algae-based flake food alongside tiny live or frozen foods such as daphnia. Apart from their difference in size, the two sexes look similar apart from the male's modified anal fin, or gonopodium. Although the species breeds readily enough, it is unusual in that the females only release one fry every day or two, rather than in one large batch. In tanks with plenty of floating plants the tiny fry are normally ignored by the adults, but wise aquarists might prefer to corral the fry into a breeding trap for the first couple of weeks.

Very rare in the trade, we're pleased to report that the Dwarf Mosquitofish is currently available at Wholesale Tropicals.

Micropoecilia parae and Micropoecilia picta

These two colourful species are somewhat like small, slender Guppies in appearance, and have sometimes been called 'Swamp Guppies' because of their preference for sluggish streams in the coastal regions of tropical South America, where the water may be moderately hard to slightly brackish.

Micropoecilia parae occurs in at least a dozen naturally occurring morphs, the "Red Melanzona" morph probably the most popular, though the blue and yellow morphs are also traded periodically. Micropoecilia parae is a good aquarium fish, but a little sensitive to 'old' water, and wild-caught specimens may even thrive best in slightly brackish conditions (a specific gravity of 1.001-1.002 being ample, i.e., around 3-4 grams marine salt mix per litre of water). It will live and breed in freshwater conditions just fine though, provided water quality is good. As with most livebearers, males are smaller but more colourful. Males also have distinctive black spot above the pectoral fin that the females lack.

Micropoecilia picta is a silvery-green species noted for the very variable colours on its dorsal and tail fins. Maintenance is similar to that of Micropoecilia parae, and again, the use of a little salt can help if your specimens are struggling to thrive. But in other regards this is an undemanding fish, and a group of them can make a very good addition to a small planted aquarium, perhaps alongside gobies and shrimps that require similar conditions. Micropoecilia breed readily, but the small fry are at risk of being eaten by tankmates, so floating plants will help to keep them safe until the aquarist can move the fry into a breeding trap for a couple of weeks.

While frequently seen in aquarium books, neither of the Swamp Guppies is common in aquarium shops, but both species are currently available at Wildwoods.

The Girardinus, Girardinus metallicus

This elegant livebearer from the brackish water streams of Cuba and Costa Rica is about the size and shape of a large Guppy, but with a beautiful metallic silver colouration (more yellowy in the artificial 'golden' morph) from whence comes the metallicus part of its scientific name. While females are fairly large, 7-8 cm being typical, the males are very much smaller, maybe 4-5 cm, and only the males have a black band or patch running from the chin to anal fin. While the Girardinus makes an excellent fish for use in hard water and low-end brackish communities, it is a bit snappy, and will go for newborn fry including its own, so floating plants are a necessity if you want to secure the fry long enough to remove them to a breeding trap or rearing aquarium.

This species turns up reasonably regularly in the better aquarium shops. The standard wild-type form can be seen at Aquatic Design Centre, while the 'golden' morph is in stock at Wildwoods.

Ameca splendens

This Mexican livebearer is an example of the Goodeidae, and as such not closely related to the Poeciliidae like the Guppies and Mollies. The Goodeidae are not widely traded, and tend to be kept and bred by hobbyists specialising in rare and unusual livebearers. Ameca splendens is the species you're mostly likely to see in aquarium shops, being very attractive and basically easy to keep. Male Ameca splendens are metallic blue, their precise colour varying from steel grey to darker midnight blue, with a vertical sulphur yellow band on their tail fin. Females look completely different, speckled black and silver, and tend to be a bit bigger, around 8 cm or so in length, compared with the males, which tend to be around 6 cm long. While Ameca splendens is lively and easy to keep, it has a reputation for being a fin-nipper, and certainly does best when kept with other active fish, such as loaches or barbs. It needs at least moderately hard water to do well, and dislikes high temperatures, around 18-22 C being ideal.

Ameca splendens are currently in stock at Wholesale Tropicals.

Two unusual Xiphophorus species

The genus Xiphophorus includes a number of familiar species, including the fish commonly called Platies and Swordtails. Xiphophorus pygmaeus is a small relative of these fishes, similar in build and colouration to a wild-type Green Swordtail, but no more than 3 cm or so in length. The two sexes look quite similar, but the males do have a short but obvious sword-like extension to the lower lobe of their tail fin. In terms of care these fish appreciate brisk currents and clean, moderately hard water conditions. They are certainly active fish and should not be kept in cramped conditions. Otherwise they are not fussy, working well in groups and consuming all the usual foods.

Xiphophorus xiphidium is a very attractive little fish, Platy-like in shape and behaviour, and making a good choice for a small planted tank. It is undemanding but will do well in medium hardness water and prefers a gentle water current. They are smaller than Common Platies though, no more than 4-5 cm in length when mature, females being bigger than the males, but only the males sporting a sword-like extension to the lower lobes of their tail fins.

Most, perhaps all Xiphophorus species will hybridise given the chance, so while both these species are interesting fish, they should be kept in separate tanks. Xiphophorus xiphidium is in stock at World of Water, Manchester, while Xiphophorus pygmaeus can be found at Abacus Aquatics.

Cardinal Livebearer, Brachyrhaphis roseni

Brachyrhaphis roseni has been in the hobby for years, but is rarely seen outside of specialist collections. It is a largish livebearer, the females around 6 cm or so in length, the males a bit less, and has a streamlined body shape similar to a Swordtail. Both sexes are metallic pinkish-green, the males possessing a red, almost sail-like dorsal fin edged with black. While females may have some of this colouration on their dorsal fins, these colours tend to be a bit more subdued.

These are boisterous, active stream-dwellers. Some aquarists have found them to be nippy, so as with Ameca splendens some care should be taken when choosing tankmates, favouring active species able to avoid trouble, such as botiine loaches or Mexican tetras. They will need a large tank with plenty of swimming space and a decent current. Water chemistry isn't critical, but as with most livebearers, moderately hard, slightly alkaline conditions are best. They will consume all the usual foods, but a good algae-based flake food should be used regularly. Breeding occurs readily, but these fish are notorious fry-eaters, so floating plants are needed if you want to have any chance of recovering useful numbers of fry. Check over the floating plants every morning, and remove any fry to a breeding trap or rearing tank for at least the next 2-3 weeks.

Abacus Aquatics

Limia perugiae

Limia perugiae is an interesting livebearer from the Dominican Republic. Midway in size between a Guppy and a Molly, the males are particularly colourful, with blue spangles on their fins, a blue-black dorsal fin, and a sulphur-yellow tail fin. Maintenance is much like that of Guppies or Mollies, to which these fish are closely related, and good quality hard water, or slightly brackish conditions, suits them well. As with other Limia species, these fish are excellent community residents, and will generally breed freely when kept properly. Floating plants are useful though, otherwise fry are at risk of being eaten.

While not often seen in aquarium shops, Limia perugiae is available at Abacus Aquatics.

Silver Halfbeak, Dermogenys sp.

This is variety of Dermogenys similar to the Dermogenys pusilla featured in many aquarium books, but as its name suggests, has an overall silver colouration compared with the grey-green colour of standard Wrestling Halfbeaks. Males sport flashes of red, black or yellow on their fins. Maximum length is around 5-6 cm, females tending to be longer and stockier than the males.

In terms of care, halfbeaks have a reputation for being a bit delicate. Stable water chemistry is important, ideally water of medium hardness and a neutral to slightly basic pH. The addition of a little salt, 2-3 gram/litre, can be helpful but is not essential. Good water quality is important, though strong water currents are not appreciated. All halfbeaks are surface feeders, enjoying wingless fruit-flies and other such live foods best of all, but also taking good quality micro pellets as well. Frozen foods such as bloodworms are useful too. Breeding halfbeaks takes a bit of effort. The males are aggressive towards each other, so shouldn't be overcrowded. Females are easily harassed to the point where they miscarry, so lots of floating plants should be provided to ensure females have shelter when required.

For the aquarist after a most unusual livebearer, Silver Halfbeaks can be obtained from the Aquatic Design Centre.