Guppy (Poecilia reticulata): care, breeding and setup

The guppy (Poecilia reticulata) is a livebearer from Venezuela, Trinidad and Guyana that entered the hobby in 1908 and has been bred into dozens of fancy strains since. Delta, ribbon, cobra, mosaic, tuxedo — colour patterns are endless. The perfect 'first aquarium' fish: hardy, colourful, eat anything, breed themselves. The one catch — without population control, 6 guppies become 60 within six months.

Tank size and water parameters

Minimum 38 L for a group of 6–8, optimum 60–80 L. Temperature 22–28 °C, pH 7.0–8.2, gH 8–20, kH 4–10. Guppies love hard alkaline water — the opposite of neons and most South American fish. Chlorine must be neutralised with conditioner. Aeration isn't needed if there's normal surface turbulence.

Sex ratio

Key rule: 1 male per 2–3 females. With more males, females get harassed constantly and stress themselves to death. If you want zero offspring — keep males only (they're brighter, no breeding). All males — no aggression problem, unlike bettas. All females — minimum drama, no bright colour.

Feeding

Guppies are omnivores. Base diet: premium flakes (TetraMin, JBL NovoBel) 1–2 times daily in small portions. Once a week — frozen brine shrimp, daphnia or bloodworms to boost colour and condition females. Vegetable supplement (blanched spinach or spirulina flakes) once a week. A fast day is mandatory — guppies are prone to obesity.

Breeding — effortless

Females are pregnant for 21–30 days. Pre-birth signs: dark gravid spot near the anal fin and a stretched belly. They drop 20–80 fry in one go, up to 200 in larger females. Fry swim and eat from minute one. With no removal, parents eat a chunk — in a densely planted tank (mosses, floating plants) 20–40% survive.

Want population control? Add 3–4 neons or panda corys — they eat fry and leave a 5–10% natural surplus. Want bulk breeding? Set a 10 L grow-out tank with plants, move the pregnant female in 2–3 days before birth, move her back out after.

Tankmates and diseases

Compatible: mollies, platies, neons, cardinals, corydoras, otocinclus, amano shrimp. NOT compatible: bettas (shred fins), tiger barbs (fin-nippers), angelfish (eat fry), any cichlids. Typical diseases: ich at low temperature, fin rot from poor water, fungus on the tail after fights. Details in our [diseases handbook].

The guppy is a textbook fish. If yours die, the problem isn't the guppy — it's the aquarium: check temperature, ammonia, nitrite and stocking density.

Lifespan

In shop conditions and poor water — 6–12 months. In a proper aquarium — 2–3 years, records up to 5. Fancy delta males live shorter — 1–1.5 years because of the cardiovascular load of a long tail. The wild form (Endler livebearer) — up to 3 years.