What Do Pets Need
Your answer

What do guppies need?

Guppies need a heated, filtered tank of at least 45 liters (11.9 gallons), and company: keep three or more.

Your tank

Your tank against each minimum

What to get

What to get

As an Amazon Associate, What Do Pets Need earns from qualifying purchases.

How many, and which kind

OATA suggests keeping at least three guppies together, two females to each male, to reduce stress on the females and the rest of the tank. Traditional guppies grow to about 5 cm, and Endler guppies, a smaller species, to about 2.5 cm.

OATA gives guppies a pH of 7.0 to 8.0.

Tank mates

Guppies shouldn’t share a tank with any fish that might nip their fins, such as barbs. Endler guppies shouldn’t be kept with any fish large enough to eat them (OATA).

Common questions

How many guppies can go in a 10 gallon tank?

None, by OATA's minimum: a 10 gallon tank holds about 37.9 liters, under the 45 liters OATA gives for a small group of guppies.

Can I keep just one guppy?

OATA says guppies need some company and suggests at least three, with two females to each male.

Keep going

How many fish can go in my tank?What size aquarium heater?What size aquarium filter?Fish and shrimp

Where we get our information from

Care and tank sizes come from OATA and RSPCA, and filter flow from Aqueon. Checked against published data from RSPCA, NIST, OATA and Aqueon.

See all 5 sources
  • NIST Handbook 44 (2024), Appendix C: 1 US gallon = 231 cubic inches = 3.785 liters (PDF)
  • RSPCA, Ornamental fish: Environment (“Choosing an aquarium”)
  • RSPCA, Ornamental fish: Diet
  • OATA, How to care for guppies and mollies, September 2022 (PDF)
  • Aqueon, “How to Choose the Best Filter for You and Your Tank” (maker article)

General care guidance from animal welfare charities, vets and makers' published sizes. It isn't veterinary advice: if your pet seems unwell or has eaten something it shouldn't, call your vet.