Guppy

Scientific name: Poecilia reticulata

Adult size: up to 6 cm, males smaller

Origin: northeastern South America and the southern Caribbean

Water: 17–28 °C, pH 7.0–8.5, 8–30 dGH

Group: several females to each male

Diet: omnivore, accepts most foods

Temperament: very peaceful, prolific livebearer

The guppy is sold in dozens of strains that differ in tail shape and colour rather than in care, from plain wild-type fish to long-finned fancy forms in red, blue, yellow and metallic patterns. Females reach up to 6 cm and males stay smaller. The species is native to northeastern South America and the southern Caribbean, including Venezuela, the Guianas and Trinidad, though the fish in the hobby have been bred in captivity for generations. It is a livebearer: young are born free-swimming, and a mixed-sex group produces them steadily. Seriously Fish gives a gestation of four to six weeks and 5–100 young per brood, and notes a female can keep producing for six months or more after mating even with no male present. Keep several females to each male, because males pursue females relentlessly. It is hardy, adaptable and very peaceful, and it generally prefers harder, slightly alkaline water. Wild fish are mainly insectivores; tank-bred guppies accept most foods.

Water: 17–28 °C and pH 7.0–8.5, hardness 8–30 dGH, so neutral to alkaline and moderately to very hard. GH measures dissolved minerals; guppies do best when it is not low. Regular partial water changes keep fancy strains healthy.

Tank and planting: a planted tank with floating plants or moss for fry cover, gentle flow and no fin-nipping tankmates for long-finned strains.

Feeding: quality flake or granules with some vegetable content, plus small frozen or live foods such as daphnia, brine shrimp and bloodworm. Feed small amounts once or twice a day.