Guppies Fish Care: Tank Size, Tank Mates and Lifespan

Guppies are small, hardy livebearing fish from northeast South America, and one of the most popular freshwater fish for beginners (PetMD). The name honours Robert John Lechmere Guppy, who sent specimens from Trinidad to the Natural History Museum in London in the 1860s (Wikipedia).

Males and females look so different that new keepers sometimes think they are two species:

• Males: smaller, 1.5 to 4 cm, with large, colourful tails and fins, and a rod-like anal fin called the gonopodium used in mating (Wikipedia)
• Females: larger, 3 to 7 cm, rounder and usually grey or plainer (Wikipedia, Flip Aquatics)

Fancy strains such as tuxedo, dragon, lace and 'dumbo ear' are all the same species. If you want to check what you have, photograph the fish side-on with the tail spread; the FishLens app identifies it.

Keep at least three, and four to six is better, with two or three females for each male (PetMD). Chewy gives the same ratio. The ratio matters because males chase females constantly, and a single female with several males is harassed without a break.

For tank size, PetMD's rule is 5 gallons for one adult guppy plus 2 gallons for each additional fish, so three guppies need about 9 gallons. Chewy and Flip Aquatics both point to about 10 gallons as a starting size for several guppies and their fry.

An all-male group avoids babies entirely, while any mixed group will breed.

Yes. PetMD calls them one of the most popular fish for beginners because they are hardy, and Chewy calls them a great introduction to fishkeeping. Wikipedia notes they tolerate an unusually wide range of conditions, including water up to 150% of seawater salinity.

The part beginners underestimate is breeding. Wikipedia gives gestation of 20 to 60 days at 25 to 27.8 C and broods of 2 to 200 fry, typically 30 to 60, and females start reproducing at 10 to 20 weeks old. Three females can therefore produce well over a hundred fry in a couple of months. Plan before you buy: keep males only, have a second tank ready, or arrange with a local shop or club to take the young.

Basic care from PetMD and Chewy: water 72 to 82 F with small daily swings, pH 6.8 to 7.8, 10 to 25% water changes every two to four weeks (Chewy), and feeding one to three times a day only what the fish eat in one to two minutes.

About two to three years. PetMD gives 2 to 3 years with proper care and Chewy up to three years. Wikipedia says wild guppies typically live around two years, and that females reproduce from 10 to 20 weeks old until 20 to 34 months.

Health signs to watch, from Chewy: a healthy guppy has bright colour and swims actively; white spots, loss of appetite, fins that recede and a bloated body are signs to act on.

Calm, small, warm-water fish. PetMD lists cory catfish, danios, gouramis, mollies, platies, rainbowfish, rasboras, swordtails and tetras. Chewy adds that the tetras should be the less aggressive kinds.

Avoid:

• Goldfish: PetMD says they need cooler water and can grow large enough to eat guppies
• Fin-nipping or large fish: a male guppy's long tail is an easy target, and any fish that can fit a guppy in its mouth will try
• Endler livebearers, if you want pure lines: Wikipedia notes Endlers cross freely with guppies and the hybrids are fertile

Bettas are often suggested too, but a male betta can mistake a colourful male guppy for a rival; see our betta fish page for its tank-mate rules.

Guppies have been released around the world, including for mosquito control, and Wikipedia reports that they have harmed native fish in many places where they became established. Rehome unwanted guppies through a shop or club instead.

Prices on Flip Aquatics' guppy page, checked 25 September 2026: assorted guppies $7.99 (on sale from $8.99), pink tuxedo from $7.99, red metal dragon and double sword from $9.99, purple haze from $12.99, red lace, pigeon blood and blue tarzan from $14.99, and a green delta breeding pair $29.99.