Guppy

Poecilia reticulata

Also known as: Million fish, Rainbow fish

Water Parameters

• Temperature: 17–28°C
• pH: 7–8.5
• Hardness (GH): 143–536 ppm (8–30 dGH)

Values above are general hardness (GH). For carbonate hardness (KH), the buffer that keeps pH stable, see the water parameters guide.

Care Summary

One of the most popular and prolific freshwater fish in the hobby, prized for vivid colour patterns and easy breeding. Livebearers: females produce free-swimming fry every 4–6 weeks without intervention, which can become a population problem in mixed tanks. Modern fancy guppies are less hardy than wild-type strains due to inbreeding; expect a shorter lifespan and higher disease susceptibility than older sources suggest. Active, sociable, and visible: an excellent first community fish. They also like well-buffered water: a moderate to high carbonate hardness (KH) holds the pH stable and slightly alkaline, whereas soft, low-KH water can let it swing and stress them.

Tankmates

Best kept in groups with at least two females per male to prevent the males from harassing any one female. Long, flowing tail fins make them targets for fin-nipping species and most bettas. Adult shrimp coexist well, but fry will be eaten. Prefers harder, alkaline water, and is well-suited to most Australian tap water.

Compatible with

• Bronze Corydoras
• Harlequin Rasbora
• Platy
• Swordtail
• Molly
• Mystery Snail
• Cherry Shrimp
• Otocinclus

Avoid keeping with

• Betta
• Angelfish
• Fin Nippers
• Large Cichlids
• Endler's Livebearer
• Zebra Danio
• Tiger Barb
• Rosy Barb
• Bumblebee Goby

Common Problems

• fin rot
• ich
• guppy disease (Tetrahymena)
• inbreeding-related weakness in fancy strains
• overpopulation from uncontrolled breeding

Sources: seriouslyfish.com, fishbase.org · Last updated: 2026-06-18