Yellow Guppies

Yellow guppies (Poecilia reticulata) are a selectively bred form that groups different strains with yellow as the dominant colour. They have an elongated body flattened on the sides and a pointed head. Males reach 3 cm, females up to 6 cm. Males display brighter colours and diverse fin shapes, including fan-tail and sword-tail variations. Females have a more modest colour, often with a silvery-olive sheen, and mature females show a dark pregnancy spot near the anal fin.

The wild form of Poecilia reticulata inhabits fresh and brackish waters in the northeastern part of South America and the Caribbean islands. Guppies prefer densely planted areas with slow current or still water. Thanks to their high adaptability, they have been successfully introduced worldwide in tropical and subtropical regions. In nature, they live in shallow waters warmed by the sun.

These are peaceful, active and schooling fish suited to community tanks with other non-aggressive species of similar size. There are no intraspecific conflicts. Guppies tend to stay in the upper and middle water layers. They show curiosity and high activity, making them popular for observation.

Most guppy strains and virtually all guppy types display impressive hardiness and low demands for care conditions. A small group of 3–5 fish needs a tank of at least 40 litres — roughly 45 × 30 × 30 cm. Your aquascaping preferences determine the décor style, as this matters little to these fish. In small volumes, water quality becomes critical and depends directly on stable filtration and regular tank maintenance. Weekly care includes removing waste and uneaten food, partial water changes with fresh water, cleaning glass and decorations, and checking equipment. Preparing the water is straightforward, as these fish adapt to a wide range of water chemistry. You only need to let tap water settle before use. For feeding, guppies readily eat any food of appropriate size — dry, live or frozen. Overall, all guppy strains have a friendly temperament and coexist well with other peaceful species of similar size (see the relevant article for more details). No aggression or rivalry occurs within the species.

Guppies are omnivorous. In the aquarium they readily accept any food type: dry flakes, pellets, and frozen or live foods of suitable size. To maintain colour brightness and health, vary the diet with plant-based components. Feed in small portions once or twice a day to avoid soiling the water with leftovers.

Guppies are livebearers; fertilization occurs inside the female's body. Sexual maturity arrives early, around 3 months. Spawning requires no special conditions: after mating, the female carries fry for about 3–4 weeks. A single brood produces roughly 20 fully formed fry. For the fry to survive in a community tank, dense plant cover is essential; the young hide among the plants from adults.

The species has a strong immune system, though highly bred forms may be sensitive to water quality and prone to degenerative changes from uncontrolled inbreeding, such as spinal curvature. Common problems include fin rot and ich. Prevention lies in maintaining stable water parameters, regular filtration and water changes, and avoiding overstocking.

When buying, choose active fish with clean fins and no coating or spots on the body. Avoid individuals with spinal deformities (hunchback) and signs of poor condition. Healthy guppies show interest in their surroundings and food. Buy from reputable breeders to minimize the risk of acquiring fish with weak genetics.