Poecilia reticulata
Guppy
Guppies are colourful, hardy and prolific, making them an excellent introduction to keeping a balanced planted aquarium.
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At a glance
- Scientific name
- Poecilia reticulata
- Family
- Poeciliidae
- Origin
- Northeast South America and the Caribbean
- Lifespan
- 2–3 years
- Adult size
- 3–6 cm
- Weight
- Under 2 g
- Temperament
- Peaceful, active and constantly on the move
- Activity level
- High
- Social needs
- Keep in groups; one male to two or three females to reduce harassment
- Intelligence
- Recognises feeding routine
- Noise
- Silent
Housing and environment
- Housing
- Minimum 40 litres, cycled, heated and gently filtered
- Space requirement
- Plants and floating cover for fry and for resting females
- Temperature
- 22–28°C
- Humidity
- Not applicable
- Exercise
- Open swimming space with planted margins
- Grooming
- Weekly water changes and testing
Life stages and changing needs
Expanded care guidance · Updated 7 October 2026 · Not professionally reviewed
Young animals and settling in
Young livebearers are miniature free-swimming fish, not eggs attached to plants. If fry appear, provide cover and an intake guard, and check that food reaches them without fouling the water. A crowded breeding box is not a long-term nursery. Plan homes and filtration capacity before intentionally breeding; never release surplus fish into drains, ponds or waterways.
Adult care and reproductive changes
Adults may breed repeatedly, and females can produce later broods after separation from males. Watch for persistent chasing, damaged fins and fish hiding from companions. Add visual barriers and reassess stocking rather than assuming harassment is harmless. A single-sex group can avoid ongoing reproduction, but it still needs adequate space and compatibility monitoring.
Later life and changing needs
There is no reliable birthday at which these fish become senior. Follow the individual: body condition, swimming control and ability to reach food matter more than a calendar label. A fish becoming thin or inactive needs water tests and a health assessment; ageing does not explain ulcers, rapid breathing or a sudden loss of appetite.
Diet and feeding
Small flake or micro-pellets plus frozen brine shrimp and some vegetable matter
Use a complete food intended for the species, with appropriate plant ingredients, rather than treating algae as a complete ration. Choose particles small enough to swallow and offer variety through suitable prepared or frozen foods. Bread, kitchen scraps and mammal meat do not provide balanced fish nutrition. Store food dry and replace stale supplies.
Feed small amounts while observing every fish, including timid individuals. Remove uneaten food and reduce the next portion if it accumulates. More food means more waste, not necessarily faster healthy growth. A change in appetite should prompt checks of temperature, ammonia, nitrite and other species-relevant water parameters before adding medications or changing multiple variables.
Daily care and ongoing checks
Every day
Each day check filter flow, heater operation where used, swimming, respiration and feeding response. Count fish and inspect for injuries. A mature biological filter is essential before stocking; clear water can still contain harmful nitrogen waste. Treat replacement water for chlorine or chloramine and avoid sudden temperature or chemistry changes.
Regular maintenance and prevention
Keep a log of water tests, partial water changes and new arrivals. Base maintenance on test results and stocking, not a fixed promise that one weekly change fits every aquarium. Preserve filter bacteria by avoiding untreated tap-water rinses of biological media. Use separate quarantine equipment and ask an aquatic vet about an appropriate quarantine plan.
Behaviour and compatibility
Display, courtship and constant grazing
- With children
- Very good first aquarium fish
- With other animals
- Compatible with other small peaceful species; avoid fin-nippers
- Training difficulty
- Not applicable
Health
- Ich
- Fin rot
- Columnaris
- Camallanus worms
- Inbreeding-related weakness
Quarantine new fish for two to four weeks before adding them to a display tank
Special care requirements
They breed constantly — plan for population control or keep single-sex groups
Breeding, feeding and adult stocking
Guppies are livebearers, and an apparently single female may already be carrying young. Dense planting can shelter fry but does not solve future crowding. Before adding fish, decide whether you can provide separate growing space or responsible rehoming; an endless cycle of births is not a sign that the aquarium has unlimited capacity.
Long-finned males can be harassed by unsuitable tank mates. Watch individuals at feeding and during quiet periods, not only when everyone comes to the front glass. Confirm that water hardness and temperature suit the stock, and assess the tank as a complete system rather than using a “fish per litre” rule.
Before you take one on
Sources and further guidance
These welfare and veterinary resources inform general husbandry advice; they do not certify this profile or replace a species-experienced professional. Confirm exact environmental settings and feeding plans for your animal.
Can your home meet guppy needs?
- Plan for a lifespan of 2–3 years, including holiday cover and, where one is available, a vet familiar with this species. Lifespan ranges are not guarantees.
- Arrange the social setting before arrival. Social guidance for this species: Keep in groups; one male to two or three females to reduce harassment. Do not assume another animal of any species is a suitable companion.
- Habitat priority for this species: Plants and floating cover for fry and for resting females. Make sure your setup can provide this consistently. Check temperature and water quality with a thermometer and test kits rather than guessing.
- Key care point: They breed constantly — plan for population control or keep single-sex groups. Discuss diet and any specialist needs with the supplier, rescue and a vet who treats this species, and check local legal requirements before acquiring an animal.
Educational reference, not an individual diagnosis or a verified professional review. Read our editorial policy.
Guidance libraries and further reading
These organisations publish relevant guidance. Their links are further reading, not evidence that they have reviewed this page.