Guppy
Poecilia reticulata
Colourful livebearer that breeds readilyBeginner
- Lifespan
- 2-3 years
- Size
- 3-6cm / 1.5-2.5in
- Social needs
- Social; keep in groups
- Time
- 10-15 min daily; weekly water change
- Cost
- Low
- Diet
- Omnivore (flake, micro-pellet, veg, live foods)
Overview
What is this animal?
- Guppies are small, peaceful livebearers native to northeastern South America, with males known for their patterned tails.
- Hardy and adaptable, they are among the most widely kept aquarium fish.
- They breed readily in the home aquarium, which is part of their appeal and also their main pitfall.
- A mixed-sex tank quickly fills with fry, so plan for population control or a single-sex group before you buy.
Temperament
- Guppies are sociable, active, and peaceful, best kept in groups where they shoal loosely.
- Males court females persistently, so a higher ratio of females, or a males-only tank, reduces harassment.
- They mix well with other calm community species but may have their fins nipped by boisterous tankmates.
- A mixed group will produce fry continuously, which adults will eat unless plenty of cover is provided.
A good fit for
- Absolute beginners and children's first tanks
- Community aquariums with peaceful species
- Keepers who enjoy colour and breeding
- Planted nano and shelf aquariums
Common mistakes to avoid
- Unplanned breeding overwhelming the tank
- Buying weak, mass-bred stock prone to disease
- Keeping males with too few females
- Assuming hardiness means dirty water is fine
Enclosure
Minimum 38 litres (10 US gallons) — for a group of 3
Cannot be kept alone. The minimum is 3, and the space above is for that group.
- A heated, filtered, cycled tank of at least 38 litres (10 gallons) suits a small group.
- Hold the temperature at 22-26C (72-79F).
- Guppies prefer slightly hard, alkaline water and appreciate planting for cover and for fry to hide among.
- They are gentle swimmers and dislike strong currents.
- Keep nitrate low with weekly partial water changes, as guppies are sensitive to dirty water despite their reputation for toughness.
- A secure lid prevents the occasional jumper from escaping.
Supplies
Setup
- Tank and stand
- Filter
- Heater and thermometer
- Substrate, plants and decor
- Liquid test kit
- Dechlorinator and starter supplies
Ongoing
- Quality tropical flake or micro-pellet
- Spirulina or vegetable flake
- Frozen brine shrimp and daphnia
- Frozen or freeze-dried bloodworm
- Veg clip for courgette and spinach
- Baby brine shrimp hatchery or frozen equivalent for fry
- Fine net for removing leftovers
Safe substrate: Inert aquarium gravel · Fine, smooth sand · Aquasoil for planted tanks
Care routine
Daily
- Check temperature and equipment
- Feed
- Head-count and look everyone over
Weekly
- Top up evaporationevery 3 days
- Clean glass and clear algae
- Test the water
- Water change and gravel vacuum
Monthly
- Trim and thin the plantsevery 2 weeks
- Check supplies and reagent dates
- Review the fry plan
- Rinse the filter media
Less often
- Replace chemical filter media (Carbon/Purigen)every 2 months
Vet: Quarterly stocking and health review — every 3 months
Top resources for more info
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Diet
- Guppies are omnivores and do best on a varied diet.
- Offer a quality flake or micro-pellet as the staple, rotating in blanched vegetables, spirulina, and frequent treats of frozen or live brine shrimp, daphnia, and bloodworms for colour and condition.
- Feed small amounts once or twice daily, only what is cleared in a minute or two.
- Their small stomachs make overfeeding easy, which fouls water and contributes to obesity and bloating in well-stocked tanks.
Health
- Mass-bred guppies can be genetically weak, so buy from reputable sources and quarantine new arrivals.
- Common problems include fin rot, ich, and protozoan ailments that follow chilling or unstable parameters.
- Stable warmth and clean water prevent most issues.
- Watch for clamped fins, white spots, or a wasting, hollow belly that can signal internal parasites.
- Acclimatise slowly to avoid temperature and pH shock, and avoid overcrowding, which is a frequent trigger for outbreaks.
Is your enclosure big enough?
Is this urgent?
In a fish tank the patient is usually the water. Test before you treat — dosing a healthy tank for a disease it does not have makes things worse.
Go now
Today
Soon
Never add a new fish to a tank that is not fully cycled, and never treat blind. A test kit is cheaper than the fish.
This is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it — and the time to find one is before you need one.
What it really costs
Setup, monthly, first year and across a whole life, itemised and with the electricity worked out from the actual wattage. Published figures for the same animal disagree by a factor of four, so the calculator shows ranges rather than picking one.
Bedding and substrate
Substrate in an aquarium is a filter as much as a floor. Most of the biology lives in and on it.
Safe
With a caveat
Never
This is our general list for freshwater fish. We have not built one specific to Livebearers yet.
My kit says 0.25 ppm. Is that dangerous?
A liquid kit measures total ammonia, but only the un-ionised fraction is really toxic, and that fraction is governed by pH and temperature — each whole pH unit multiplies it roughly tenfold. So the same reading can be nearly harmless in one tank and lethal in another; this works out which one you are in.
Compare with other animals
The same axes for every animal, side by side — the way the guides are written makes that a fair comparison rather than two articles.
Livebearers, side by side
Same axes, same care guides — the honest way to choose between types.
See all Livebearers side by side →
