Information about the tropical platy. Gestation, breeding and history. We no longer sell live tropical fish, until our re-modeling is complete. We do however, provide information on fish and diseases, water pets and fish tank selection and care.

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The Platy

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The Platy was first found in Mexico by Guenther in eighteen-sixty-six. In this section of the Moon and the Variatus, it will be considered the same as the platy since they are very close cousins.  Today, there are a large variety of platy in a wide range of sizes, colors, body and fin types. Platy’s are hardy and undemanding.  They are an easy tropical fish to raise and breed.  They are a peaceful and sociable fish and ideal for community aquariums.  The platy has well rounded fins and a deep body.  The moon shaped spot on the tail is why, they are sometimes called Moon’s.  Platy’s are essentially non-aggressive and should not be kept with aggressive fish.  They can be kept in a single species aquarium. Different strains of platy’s should not be mixed with other strains of platy’s, Moon’s or Variatus will interbreed. They will also, interbreed with Swordtails.  The results from these inter-breedings will produce pet fish with unpredictable outcomes. It is fine to keep these different varieties in a community tank if not used for pure and true line purposes.  Different strains should be kept in separate tanks if someone is trying to maintain a pure bred genetic true line of platy’s.  Platy origins are Central America from Guatemala to Central Mexico.  Their natural habitat is in slow moving streams and ponds.

Platy’s are a live bearing and long toothed carp. Water temperature should be kept at sixty-four to seventy-eight degrees F. They like hard water (one-hundred to one-hundred and fifty mg per liter). The water should be alkaline and kept at a pH of seven point five.  Water plants should be planted, not only for the platy’s to nibble on but, to provide cover for their young to escape them.  The adult platy’s are cannibalistic in that they will eat their young.  Adult platy’s should be kept in separate tanks from their young. It is advised that the pregnant female be placed in a holding tank and be closely observed so, that removing her, from the tank as soon as the young ones are born, can be easily accomplished.  Different types of breeding traps are available at pet stores for the protection of the young pet platy’s.  Platy’s like protective cover with densely planted plants.  Water plants should not only be planted on the sides but, at the back of the aquarium because the platy loves plenty of space to swim.  A loose cover of floating plants is good.  Water-sprite and Spirulina are recommended.  The substrate (gravel) should be dark in color.

The gestation period of the platy is thirty to fourty days, mostly dependant on water temperature. First broods are small of about ten offspring. Brood size increases in numbers with each successive brood and to number up to seventy-five to eighty per brood as the female grows larger.  The larger the female, the larger the number of young ones that she will have born.  Size of the female, when adult is about three inches long with the male being somewhat smaller.  The males reproductive organ is called the gonopodium. The gonopodium is a modified anal fin.  The females anal fin is rounded where the males gonopodium is long and tubular. The gonopodium allows internal fertilization of the eggs inside the female platy.  The gonopodium is an organ of copulation and, when mating, is inserted into the female where some of the sperm fertilizes the female eggs and the rest is deposited and stored, in the folds of the female fish ovarian tubes.  Females kept alone, after being bred once, will continue to have successive broods of offspring without having to mate again.  The sperm stored in her ovarian tubes is utilized and she may give birth six to nine times in her life.  Each successive brood will be larger than the previous one.  The young grow as eggs inside the female and then, they break out of the egg, being born alive and free swimming.  The pregnant female pet platy can be readily detected of sexual gender because she will have a dark mark in front of the anal fin.  This is called the gravid spot and becomes quite noticeable as she approaches giving birth.

Genetic breeding is difficult because after the first breeding, the female retains the sperm for the rest of her life.  If a desired male is selected for breeding with a previously bred female, the offspring that result will be mixed with the genetic characteristics of all previous mating with other males.  The majority of the offspring may carry the genes of the most recent breeding.  The only way to assure a true line of genetic offspring is to breed a desired male to a virgin desired female.  Females, for this purpose should be separated from males at the earliest time in their life before mating occurs.  Young males can be recognized by their distinctive gonopodium which appears at about three or four weeks of age.  Male and female platy’s should be transferred to a separate holding tank for arranging true line of genetic offspring. Platy’s become sexually active from about three months of age on up.

The Platy’s diet should be varied and should consist of dried prepared foods plus, small live foods such as brine shrimp, bloodworms or tubifex worms.