Guppy
Guppies (Poecilia reticulata) are hardy, colorful livebearers for a cycled tank of at least 10 gallons with hard, slightly alkaline water. They breed constantly, so an all-male group avoids a population explosion.
Guppy at a glance
- Scientific name
- Poecilia reticulata
- Adult size
- ~2″
- Temperature
- 72–82°F
- pH
- 6.8–7.8
- Minimum tank
- 10 gal
- Temperament
- peaceful
- Social
- schooling — keep 3+
- Reference
- Wikipedia
The guppy (Poecilia reticulata) is the classic beginner fish: hardy, cheap, endlessly colorful, and active. The one thing every new keeper learns the hard way is how fast they breed.
Tank and groups
Keep guppies in a cycled, heated tank of at least 10 gallons, in a group of 3 or more. They are social and active. The real stocking question is breeding, not space: a mixed-sex group multiplies quickly. An all-male group of 5–6 stays colorful and stable in a 10-gallon. See how many guppies in a 10-gallon tank for the numbers.
Water
Guppies prefer hard, slightly alkaline water, around 72–82°F and pH 6.8–7.8. They tolerate a wide range but do best with stable, mineral-rich water. A heater and filter are still required.
Diet
Feed a quality flake or micro-pellet as the staple, with frozen or live brine shrimp and daphnia for color and condition. Small amounts once or twice a day; they will beg constantly.
Breeding
Guppies are livebearers that breed without any effort on your part. One male and a couple of females become 30-plus fish in a few months. If you do not want a population explosion, keep all males, or have a plan for the fry.
Temperament and tankmates
Guppies are peaceful, but their bright, flowing tails make them a target for fin-nippers and a trigger for some aggressive fish. The good companions and the ones to avoid (from our compatibility model) are listed below.
Compatible tankmates for Guppy
Generated from our compatibility model — temperament, fin-nipping, temperature overlap and predation. Run your exact plan in the calculator below.
Good companions:Neon tetra, Ember tetra, Cardinal tetra, Harlequin rasbora, Endler's livebearer, Platy, Molly, Corydoras catfish, Pygmy corydoras, Otocinclus, Kuhli loach, Dwarf gourami, Angelfish, Cherry shrimp, Nerite snail, Mystery snail.
Avoid:Zebra danio, Tiger barb, Serpae tetra, Betta.
Plan a Guppy tank
Start with the centerpiece and check stocking, filtration and compatible tankmates — live.
Planning a Guppy tank. We start with your guppy and filter the list to compatible tankmates — untick to see every species (incompatible ones get flagged).
Stocking — under 85% comfortable · 85–100% full · over 100% overstocked
Show the math
FAQ
- How many guppies in a 10-gallon tank?
- About 5–6 adults. Keep them all-male to avoid breeding; a mixed group can turn into dozens of fish in months. See our full breakdown of how many guppies fit a 10-gallon.
- What water do guppies need?
- Hard, slightly alkaline water suits them best, roughly 72–82°F and pH 6.8–7.8. They are hardy but still need a cycled, heated, filtered tank.
- Do guppies need to be in groups?
- Yes, keep at least 3, and ideally more. They are social livebearers. All-male groups stay colorful without breeding; mixed groups multiply fast.
- Are guppies good for beginners?
- Very. They are hardy, active, and cheap, which is exactly why so many first tanks start with them. The main beginner trap is overstocking from uncontrolled breeding.