Order Cyprinodontiformes
Suborder Cyprinodontoidei
Family Poeciliidae
Subfamily Poeciliinae
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Genus Xiphophorus
— Southern Platyfish, or Platy — Xiphophorus maculatus [Gunther, 1866]. Synonym: Platypoecilus maculatus, nigra, pulchra, sanguinea. (English: Platy, Red Southern Platyfish, Red Tuxedo Platy, Red Wagtail Platy, Wild Southern Platyfish). Water bodies of the Atlantic coast of Mexico and Guatemala. Male 3-4 cm, female 4-6 cm. They lack a sword, and females can be distinguished from males by the shape of the anal fin. While swordtails living in the wild are colored almost identically—with green as the main tone—platylies in nature come in various colors. The southern platyfish forms many local races with different colorations. Light yellow fish are most frequently encountered. In addition to these light yellow fish, black and red specimens are also found in nature.
Such color diversity inspired aquarists to breed fish with even more ornate coloration. The coloration of the base form ranges from yellowish, brown to olive-brown, as well as bluish-gray to gray with a large spot near the tail and a smaller one on the back. The belly is yellow to white, and the flanks have a bluish-green tint. The gill cover is blue-green with a metallic sheen. Males feature 2 to 5 faint transverse bars on their body. The pectoral, pelvic, and dorsal fins are colorless and transparent. The lower edge of the caudal fin is blue with a metallic sheen or greenish-white.
In our aquariums, the original wild form has not been preserved. Breeding forms are represented as hybrids of X. helleri × X. maculatus × X. variatus. A characteristic feature of this species is the presence of more or less distinct dark spots at the posterior end of the caudal peduncle and the caudal fin. The presence of these spots is the reason this species is called “spotted” (maculatus — spotted). The size, shape, and placement of these spots are hereditarily determined.
Taxonomists and breeders distinguish seven main types of placement for these spots. When discussing the origin of a particular breed, the name of the spot placement type in the ancestors used to develop that breed is usually indicated: “single spot”, “twin spot”, “half-moon”, “full moon”, “half-moon with twin spot”, “full moon with addition”, and “comet”. Sometimes these spots may not develop fully. When crossed with specimens lacking these spots, the offspring in the first generation will display spots.
Identification: Southern Platyfish — Xiphophorus maculatus.
From numerous races of wild southern platyfish differing in coloration, utilizing observed mutations and crossbreeding, aquarist-breeders have developed about 40 varieties with new color and size combinations of spots not found in nature (ranging from yellow, red, and blue to black, including various color combinations) and body forms with elongated caudal fins (pointed or brush-shaped) and veil-like dorsal fins. Crossing platyfish and green swordtails (Xiphophorus hellerii) with subsequent selection allows breeders to produce swordtails featuring virtually any coloration found in platyfish.
When purchasing fish, we must ensure that each color variety is kept in a separate aquarium. Essentially, this prevents females from being fertilized by males of a different color to avoid producing fry whose colors do not match any standard. Males reach adolescence by the fourth month, and at this time, they must be separated from their sisters to prevent early mating. Pairs can be formed at six months of age.
Peaceful, omnivorous fish, somewhat more delicate than others. Small aquariums densely planted with vegetation yet providing open swimming spaces are suitable for keeping and breeding southern platyfish. Stocking density should be at least 3 liters per pair. They have no special water quality requirements, but moderately hard water with a near-neutral pH is preferred. Platies adapt well even in newly set-up aquariums. To care for these undemanding fish, the aquarium should always be well-planted with algae where the fish can graze and find not only plant matter but also microorganisms. Hardness 8–25°, pH 7–7.5, temperature 20–26°C. If the fish show signs of illness, the temperature should be raised by 2–4°C, and salt added to the water at 1–2 teaspoons per 10 liters.
They reach maturity at 4–6 months depending on the hybrid group and keeping conditions. Females give birth to fry every 28–50 days (more frequently at higher temperatures and less frequently at lower temperatures). Measuring 4–5 mm, the fry are smaller and weaker than those of other livebearers, so it is best to raise them separately from swordtail, guppy, and other fish fry.
There are numerous forms and color variations of this fish carefully selected over many years. Currently, there are many ornamental forms, including: black-spotted on a white background (pulchra), green-black (schwartz), golden (aurata), bright red (rubra), black with a metallic sheen (nigra), black-spotted on a yellow background (marble), black-finned with a red and yellow body, red-finned with a lemon body, yellow with a bluish sheen (mirror), albinos (red eyes, dark pigments absent), and other varieties, including those with extensions in the dorsal fin, lyre-shaped tails, or elongated central rays.
High-finned (scarf) forms have also been bred. In recent years, red and white disk platies with a very high, almost round body have appeared. Bright red disk platies have a shortened body that appears broadened in the middle. Favorite forms include the coral platy, moon platy, wagtail platy, Simpson’s platy, bleeding heart platy, and veil-finned varieties.
Identification: Southern Platyfish — Xiphophorus maculatus-2.
Xiphophorus variatus, Xiphophorus meyeri, Platy. 
