Guppy

This page is educational reference material for preparing questions. A licensed veterinarian examines the animal, makes the diagnosis, and sets the treatment.

Guppies, Poecilia reticulata, are the livebearing fish from northern South America and the Caribbean that now exist mostly as colorful farm strains. Males are smaller and flashier. Females are larger and almost always pregnant. Adults are about 1 to 2.5 inches and often live 2 to 3 years. Peaceful, easy, and prolific is the honest summary.

Hard water and a plan for fry

Use at least 10 gallons, more if you are keeping a group. Temperature 72 to 82°F, pH around 6.8 to 7.8, general hardness often happiest around 8 to 12 dGH. Ammonia and nitrite at zero. A gentle filter and plants give fry a chance and give harassed females a break. A ratio with more females than males reduces the constant chasing that shreds fins.

They are omnivores. A quality flake or micro pellet, plus frozen or live foods a few times a week, is plenty. Overfeeding plus a population explosion is how a "beginner tank" becomes a nitrate problem.

What hardy does not include

Guppies from big farms arrive with columnaris, camallanus worms, and fin rot more often than wild-type fish would. Quarantine new arrivals if you can. A red, clamped, or wasting fish should not be poured into your main tank with a dose of mixed medicine. Camallanus in particular looks like small red threads at the vent and needs a specific treatment, not a general cure-all.

A starter group and a 10-gallon kit often cost under $100. The ongoing cost is food, water conditioner, and whatever you do with the offspring. This is a good first fish for someone who finds the breeding interesting. It is a bad first fish for someone who wants one pet that stays the same size and count for ten years. Gasping at the surface means test the water, then read the gasping guide. The checker points the same direction.

Guppy breeding and lifespan

How long do guppies live?

Often 2 to 3 years. They are not a decade fish. A short life plus constant babies is the actual hobby, whether you planned it or not.

Will they overpopulate a tank?

Yes. A female can store sperm and drop broods for months. Keep more females than males to reduce harassment, and have a plan for fry: a separate tank, a fish room, or a shop that takes them.

What water do they like?

About 72 to 82°F, pH 6.8 to 7.8, and moderately hard water. They are a better fit for tap water that is not extremely soft than neon tetras are.

Are they beginner fish?

Yes, in a cycled 10-gallon or larger tank with a plan for babies. They are a poor beginner fish in an uncycled bowl or with a fin-nipping neighbor.