Guppy Care Guide: Tank, Breeding and Health

Quick answer

Guppies are small, hardy tropical livebearers that do best in a group in a heated, filtered tank of about 40 litres (10 US gallons) or more, at roughly 22–28 °C (72–82 °F). Keep two to three females per male, or males only if you don't want babies. They breed fast, so decide early what you'll do with the fry.

Getting to know guppies

Guppies (Poecilia reticulata) are livebearers: females give birth to free-swimming young instead of laying eggs. Males are smaller and much more colourful, with long tails, and have a modified anal fin (the gonopodium) for mating. Females are bigger, usually plainer, and grow to around 5 cm (2 in). Expect a lifespan of around 2 to 3 years.

Fancy guppies with very long, heavy tails have been bred for looks over generations. They're often less hardy than plainer or wild-type fish, so pick active, well-shaped fish rather than the showiest tail in the tank.

Tank setup

Guppies are small but active, and a group needs room. A tank of around 40 litres (10 US gallons) or more makes life easier for a small group, because a larger volume stays stable.

• Heater with thermostat. Aim for about 22–28 °C (72–82 °F). Try to keep daily swings small.
• Filter. A gentle filter works best; strong currents tire small fish with long tails. Sponge filters are popular because fry can't be sucked into them.
• Lid. Guppies can jump.
• Plants. Live plants (Java moss, hornwort, floating plants) give females a break from males and give fry places to hide.
• Water. Dechlorinate tap water. A pH of about 6.8 to 7.8 suits them, and most guppies prefer moderately hard water to very soft water.

Cycle the tank before adding fish; the steps are in The Aquarium Nitrogen Cycle, Explained Simply.

Feeding

Guppies are omnivores. A quality flake or micro-pellet makes a good base, with frozen or live foods like daphnia and brine shrimp for variety. Feed small amounts one to three times a day, only what they finish in a minute or two. Thaw frozen food first.

Guppies always look hungry. Don't believe them. Overfeeding fouls the water fast in a small tank.

How guppy breeding works

Guppies breed so readily that most keepers end up with babies whether they planned to or not.

The ratio. Males pursue females almost constantly. With two or three females per male, the attention is spread out and females are less stressed. Too many males and the females get worn down.

Pregnancy. Gestation usually runs about three to five weeks; warmer water tends to shorten it. A pregnant female gets a squarer, rounder belly, and a dark patch near the vent (the gravid spot) often grows darker as birth approaches.

Stored sperm. Females can store sperm and produce several broods from one mating. A female kept away from males may still give birth for some time.

Brood size. It varies a lot, from a handful of fry to several dozen, with bigger, older females usually having more.

Saving the fry

Adult guppies eat fry, the mother included. Your options:

• Heavy planting. Dense moss and floating plants let some fry survive in the main tank with no extra effort.
• A separate fry tank. The most reliable option. Move the fry, not the mother, once they're born.
• Breeding boxes. These hang in the tank and separate mother and fry. Use them with care: some females find the confinement stressful, so move her in only when birth is close and take her out soon after.

Feed fry tiny amounts several times a day: finely crushed flake, fry food or newly hatched brine shrimp. Small, frequent water changes keep a fry tank clean.

Plan for the numbers

Two or three females can become dozens of guppies within a few months. Before that happens, think about whether you have space, a shop or fellow keepers who'll take extras, or whether you'd rather keep a single-sex tank. Never release guppies into ponds, streams or canals; they can harm local wildlife and spread disease.

Common health problems

Most guppy illness starts with water quality or stress. Learn what normal looks like: active swimming, open fins, eager feeding.

• Fin and tail rot. Ragged, shrinking or white-edged fins. Often linked to poor water or nipping. See Fin Rot in Fish.
• White spot (ich). Salt-like white dots on body and fins.
• Fungus. White, cottony tufts, often on a wound.
• Bloating with raised scales. A sign of serious internal illness (often called dropsy).
• Clamped fins, shimmying, hiding. General signs of stress or illness.

When a fish looks unwell, test the water before reaching for medication. Many guppy losses happen right after a new batch arrives, so quarantine new fish in a separate tank for a few weeks before they join the main group. If several fish are sick or dying, or a problem doesn't improve once the water is right, get help from an aquatic vet or an experienced fish keeper.

In Pakistan

Guppies are among the cheapest and most widely sold aquarium fish in Pakistan, and many keepers breed them at home. Summer heat can push an unshaded tank above the comfortable range, which cuts oxygen in the water, so add aeration in hot months and keep tanks out of direct sun. In winter, a heater keeps temperatures steady. Shops often hold guppies in crowded tanks, which is where disease spreads, so look for clean tanks with no dead or clamped-fin fish.

Looking for healthy stock to start with? You can browse fish from verified sellers on Paalo.