This genus, described by Hubbs in 1926, has undergone several transfers and revisions during its 90-year existence (e.g., Recepoecilia and Micropoecila). It was originally created as a systematic unit for the species Poecilia vivipara parae Eigenmann, 1894 (which was hereby revised to Micropoecilia parae). Gradually, it was replaced by a long series of species with which systematists were at a loss. This fact alone makes the species of the genus Micropoecilia very interesting.
The first part of the name – micro – suggests that they are classified as rather small due to their stature. Surprisingly, without the expected exceptions.
Perhaps the largest of them is M. picta, with a size almost reaching the size of a peacock’s eye Poecilia reticulata.
Micropoecilia picta
I have been fortunate enough to breed pictas, but most importantly I have been able to observe and hunt them in the wild. The Amacuro Delta (Orinoco estuary) is one of the typical and certainly the most extensive habitats of this species. Its area is about 25 000 km2, which is almost 1/3 of the Czech Republic and 1/2 of Slovakia. It is therefore clear that finding picta in the local channels and arms is not quite obvious. But it’s not exceptional either. During my week stay in this area I “came across” them 3 times. Each time it was a location with great depth and a surface almost perfectly covered with tocoshell (Eichhornia) and babel (Pistia). I never had any luck in the shallows. Picts kept exclusively near the surface (unlike peacock eyes, which in nature are more often found in the middle of the water column or right at the bottom) and very quickly took refuge in the roots of floating plants. They were, however, quite easy to catch with an ordinary aquarium net. This was enough to “rake” the plants and there were almost always a few pieces that could be coaxed into a closer inspection.
Like hunting, breeding and rearing them was relatively easy. The conditions afforded to peacock eyes also suit them. They’re just a little more demanding of their food. They prefer a higher animal protein content and water unencumbered by nitrogen. Otherwise, they stop breeding.
One more important note on reproduction; the success rate of giving birth increases significantly if males are present at all times. Their permanent slamming of their mouths on the pregnancy spot of the females looks threatening and evokes the idea that they are about to eat the young immediately after birth. But this “massaging” is apparently important for a successful birth, as the separation of females results in delayed litters and often dead pups. These are indistinguishable from the spawn of peacock loops. So are the adult females. These must be kept strictly out of guppy breeding areas, because if they mix, you can’t separate them. There is almost no information on their possible interbreeding, everything is rather based on conjecture and assumptions. But there is information circulating among breeders of bred peacock eyes that the black-headed (so-called “Moscow”) form was created in the 1980s in the Soviet Union by crossing P. reticulata and M. picta. I don’t know, I haven’t found any relevant references to confirm or deny this, and I haven’t done any hybridization experiments myself.
The colour variation of individual populations is enormous and many times exceeds that of wild peacock loops (as indicated by their species name – pictus = colourful, variegated). You may be wondering why picts are so rarely bred. Their basic requirements are really not exceptional. In all my colleagues abroad and in the Czech Republic and finally also in my country, after some time of success the breeding simply collapsed in the 3rd-4th generation without any visible reasons. We had a lot of discussions on this topic, but we came up with nothing but the somewhat mysterious and excusable term “environmental fatigue”.
Micropoecilia minima
One of the most mysterious and rare species in this genus. In the 10 years since its description, it has been constantly torn between recognition and non-recognition as a species, and regular efforts to classify it as a form, dwarf population or colour aberration. It is currently classified as a species and listed in the genus Poecilia according to some systems (e.g. Eschemeyer). The latter, however, is so far alone with its view.
Minima is extremely rarely bred due to a number of pitfalls that its breeding entails. Even transport is problematic, as it requires warm (above 26 °C) and oxygen-rich water. So far, I have only seen success with “Breathing Bag” imports, which are the only ones capable of providing sufficient oxygenation of the water in the long term. Attempts with conventional plastic bags have so far always failed. For a short transport they would probably do the job, but I don’t know of any successful breeders of these rarities anywhere near me. In fact, the only really successful breeders who are willing to provide fish are in Japan. I’ve gotten them from them twice already. I’ve always gotten 3 pairs, they’ve always arrived alive and well, they’ve always been from a different breeder, always from a different location, I’ve always bred them, but never made it past the first generation.
For the first time I was surprised by the very strong cannibalism, which was not limited to juveniles but also to adults. Females caught and mauled males that were only about half their size. The live feeding in which the fish were constantly swimming didn’t help, nor did the very dense vegetation (the whole bottom covered with Java moss, with a thicket of roseate above and a babel on the surface), just somehow the juveniles and males were always discovered and disposed of. I’ve kept 5 pieces and never got any further.
I prepared carefully for the second attempt in advance by email questioning my colleague Taoto Ito, who has been successfully breeding minima for some time. Here is a free translation:
1) All females must be kept separately until adulthood, otherwise the males will be killed.
2) Pair the adults at a minimum size of 3 cm in a ratio of 1.3 (1 male, 3 females).
3) Gestation is 20-24 days, young are usually 10, max. 20, typical superfetation (gradual maturation of embryos).
4) Juveniles fed with artemia and dry food until maturity. Temperature constantly 27-28 °C.
5) Continuously separate the sexes as soon as they are distinguishable.
6) Change no more than ¼ of the water to the males, otherwise they fall.
7) All surface area must be covered with floating plants.
8) A gravid female may be transferred to another aquarium at least one week before giving birth, otherwise she will prematurely give birth to dead young.
9) Last water change at least 3 days before birth, otherwise see point 8.
10) Females eat the young immediately after birth – it is necessary to wait at the tank and catch them immediately.
11) Fish from the wild are long-lived (they live for 2 years), but each generation has a shorter life. Currently breeding the 7th generation. The previous one lived only 6 months.
Specific dates:
27 °C; pH 6.8-7.3; hardness 3-4 °dGH; alkalinity 0.2 °dKH;
1/2 fresh water per week, rearing essentially without salt, adults add sea salt.
Adult rearing tank 50 litres, nursery tank 20 litres and juvenile rearing tank 10 litres. Always a large number of plants.
Well, I’ve tried all of the above, but the cannibalism and constant dropping of the adults just hasn’t been overcome. And although I managed to gut about 10 fish from this second Japanese shipment, after losing them after one water change, I stopped coveting them and included them as a memento of my failures.
Micropoecilia parae
The first described species of the genus. The original description gave it as Poecilia vivipara parae, but the species vivipara was described 93 years earlier (Poecilia vivipara Bloch & Schneider, 1801) and has nothing to do with parae at first sight. It had one more brief episode with an invalid description in 1926, when Hubbs named one of its populations as Poecilia bifurca.
The fish was named after its locality, the northern Brazilian city of Pará. It does not abound in colour and is therefore more of a species to “complete the collection” of very demanding animals. Like M. minima, it thrives only in high temperatures and requires live food. In my breeding these fish have never accepted anything that did not move. Their cannibalism is about at the level of peacock loops, so almost none. However, the population did suffer from persistent intestinal tumors in adult females. They were only able to give birth until the tumours broke out. They usually only managed one litter (and sometimes not even that). Since they have about 5 pups, the additions have barely made up for the losses. After 2 exhausting years during which I had to breed them daily, the last female died and the males who did not suffer from the disease enjoyed widowhood for a few more months. The loss of this species was very sad for me, but on the other hand I was quite relieved. It was a perpetual struggle for the survival of the females, they stole too much of my time and did not bring much pleasure.
Micropoecilia bifurca
It was originally described by Eigenmann (1894) as Poecilia parae, but the same year the description was retracted, leaving the name to another species. The valid description dates back to 1909, when Eigenmann again described it as Acanthophacelus bifurcus. It was not until 1926 that it was reclassified by Hubbs to its present genus. The genus name bifurca describes the typical colouration of the marginal rays of the caudal fin (bi=two, furca=fork).
This diminutive livebearer is an ideal keeper for small beginner tanks. In the spring of 2005 I acquired 2 pairs in exchange from British aquarist David MacAllister, and by the autumn they had been bred to make their triumphant journey through central Europe. This is a population where the males do not have the forked tail fin colouration mentioned above. Females have relatively few young (usually around 20), but give birth very regularly every 20-23 days (depending on temperature), the young grow rapidly and have minimal losses. Females give birth for the first time at about 3 months, with the first males appearing at 6 weeks and sexually maturing at about the same age as females. They are equal to wild peacocks in terms of ease and reliability of breeding. They will be happy with any food, temperatures above 22 °C, slightly alkaline water and a rather small aquarium. Ideally up to 60 litres. They do not thrive so well in larger tanks.
A few months ago I put about 30 juveniles in a 200 litre paludarium as possible food for a school of Ilyodon furcidens. Oddly enough, they don’t notice them, so the agile bifurcates are always first at the food, yet they grow virtually nothing and don’t get fat. They just don’t like the large space and the presence of big fish. It is not advisable to keep them together with other species of their genus, as there is a presumption of interbreeding. Co-breeding with peacock eyes (P. reticulata) is not recommended either. It has been proven that they interbreed with the latter, as many breeders have already found out.
The genus Micropoecilia is rare in itself, and in addition to the species described above, it includes amazonica (Garman, 1895), branneri (Eigenmann, 1894) and melanzona (Eigenmann, 1909). These are species that have never been maintained for very long in Europe; at present I know of no one who has bred them. At least one still has some of that base in front of one, doesn’t one?