Platy Breeding
Xiphophorus maculatus or the platy is the color king of the livebearers. These eye-appealing fish are more than just beautiful; they are peaceful, hardy, and prolific, and deserve a place in every community tank. Also called a platy is Xiphophorus variatus, the "platy variatus."
The first platies to be exported from Mexico, the homeland of several beautiful tropical fish, went to Germany in 1907. Three years later they are said to have been brought to the United States. In the years that have elapsed since they arrived in the United States, more than a dozen popular varieties have been developed through selective breeding—each more beautiful than the other. This process of selective breeding is long and laborious, but with the proper knowledge you can
develop your own strain, provided you have the time and the space. Your reward in developing such a strain will be in the satisfaction that you have started something new. You may even have contributed something to science. Gregor Mendel will be remembered as the first one to realize, through his work with peas, that species carry certain characteristics from one generation to the other through submicroscopic, discrete particles, later called "genes." The laws that Mendel formulated are applicable to tropical fish as well as to peas and humans. If you are interested, look up a text on fish genetics and see if you would have the patience and fortitude to go through the same painstaking steps as he did.
The platy has been developed in many unusual colors and finnages; the gold-colored ones are often called "moonfish" because of the crescent-shaped spot at the base of their tails. For example, your fish dealer may say "gold platy," while calling the colored platies "red moonfish," "blue moonfish," "black moonfish," etc.
In the early 1960's platies were developed from hifin swordtails as basic stock, which had huge dorsal fins. These platies were called by various names such as "sailfin platy," "topsail platy," and "hifin platy." Nearly every color variety of maculatus and variatus platy has been bred with the huge dorsal fin.
Breeding the sailfin platy is simple, though many of the offspring usually do not show the huge dorsal of their parents. A good strain might breed 50 per cent true and an amazing strain might breed 90 per cent true, but to date there is no strain that breeds 100 per cent true.
The prices of these beautiful platies are considerably higher than the normal platy, but they are well worth it, especially if you intend breeding them.
In 1965 I was able to bring back from Hawaii the first albino variatus platies. In 1966 I found the first albino maculatus platies in Hungary. These strains were bred in Florida where they were able to propagate thousands of these delicate platies for distribution to pet shops all over the world. Eventually, the strains were lost.
Sex differentiation in the platy is not a perplexing problem. There is a marked difference between the physical characteristics of the male and female platy that enables identification; the male is shorter and of lighter build than the female; also the anal fin is an indication of sex. In the female, the anal fin is fanlike and kept spread out, while in the male the anal fin is rodlike and is kept close to the body. This is the organ the male uses to fertilize the female and it is characteristic of almost all the livebearing fish kept in aquaria. If you feel doubtful identifying the sexes, ask the fish dealer to give you two or three pairs and trust that his judgment is better than yours. However, do not worry as there is no danger of having either too many males or too many females.
Raising platies is not too great a problem. The main obstacle is keeping the temperature constant, as the platy is very sensitive to change. A thermostatically controlled heater is the best way to do this and it is indispensable with the platies. A temperature of at least 72°F. is desirable, and 75°F. is the best for breeding, but whatever the temperature is, make sure that it stays the same.
The best way to breed these fish is to give them an aquarium of their own. The platy will rarely eat its young, and therefore one of the biggest headaches of the amateur aquarist takes care of itself. Most of the other fish will eat any young fish that swims and is small enough to be gobbled up, as well as their own young, so play safe and keep the platies all alone in a large tank.
Females can have broods every four weeks and, depending upon size, health, and breeding conditions,
may drop from two to 200 at one time, though they usually average about 20. Care should be exercised with the female platy, as she is as soft and delicate as she looks; when the time is near for her to drop, she must not be excited or moved. If you move her at all, you should do it well in advance of her expected dropping or you will lose her and the brood as well.
Food for the platies is no problem as they will eat anything that they find. They will get along very well on the regular prepared dried food, with a little daphnia or some worms now and then. Gordon's formula is excellent. They are partly vegetarian and enjoy eating algae.
All the different types of Platies can be crossbred, and the results of the crossbreedings are often remarkable. The colors will, in a sense, mix, and if the fish retain the correct gene combination, this color mixture will breed true. Of course this is sometimes a difficult thing to accomplish, but it is worth the effort.
Platies have frequently been crossed with swordtails, and most of the swordtails and platies that are purchased are more or less remote descendants from such a cross. A purebred swordtail or platy is much more the exception than the rule. If you desire to try this cross, make sure that you have a large tank with plenty of foliage for the young to hide in, as the female swordtail, as well as the male, will eat the young.
Young platies are hard to distinguish from the young of other types of livebearing fish. They are one of the most delicate types and are susceptible to all the evils of bad tank management. They will grow swiftly and be healthy if kept in the proper type of tank, with lots of room, a constant temperature, a normal pH, and plenty of vegetation. They will mature in about eight months (less in some aquarium situations). The following example will illustrate the importance of having optimum conditions for the growth of these young fish.
A typical brood of 22 was divided into two groups of 11 each. One group was put into a 15-gallon tank, which they had all to themselves—plenty of room, constant temperature, and live food every other day. The other group was left to their own devices in a tank of the same size but with many other fish. Of the 11 in their own tank, nine matured and reproduced in eight months; the group in the crowded tank took ten months to mature, and only two were alive at the end of that
period.
Of course, separating all the young fish is a prohibitive task for the beginning enthusiast, but the idea should be kept in mind that it is better to have ten healthy fish than 20 unhealthy ones.
The varieties of Xiphophorus need the same general care as the common variety.
