Southern platyfish

The southern platyfish or common platy (Xiphophorus maculatus) is one of the most popular and widely kept freshwater aquarium species, native to the Atlantic coastal drainages of Mexico, Guatemala, Belize, and Nicaragua. A small livebearer reaching 5 cm (2 in) for males and up to 7.5 cm (3 in) for females, it is valued for its peaceful nature, dazzling array of selectively bred colour morphs, and remarkable ease of breeding. Virtually all platies in the hobby today are captive-bred — wild specimens are almost never seen in the trade.

Platies are very peaceful community fish that thrive in groups of six or more in a planted aquarium of at least 60 cm length (~54 L / 15 gal). They are undemanding but have a firm requirement for moderately hard, alkaline water: pH 7.0–8.2 and hardness 10–30 dGH. They will not thrive in soft, acidic conditions. A well-planted tank with open swimming areas, gentle filtration, and a secure lid suits them best — they are known to jump, especially during acclimation. They prefer "older" water, so 25% water changes every two weeks are typically sufficient.

As omnivores, platies accept virtually all aquarium foods: high-quality flake or pellet as a staple, supplemented with live or frozen brine shrimp, Daphnia, and bloodworms, plus vegetable matter such as spirulina flakes and blanched spinach. Breeding is straightforward: females give birth to 20–80 live fry every 4–6 weeks after a single mating (they store sperm). Keep a ratio of at least two to three females per male to prevent harassment. Fry are large enough to accept brine shrimp nauplii and powdered flake immediately. Typical lifespan is 3–5 years.