Photo: Nevit Dilmen (talk) (CC BY-SA 3.0) — via Wikimedia Commons
Guppy (Poecilia reticulata)
Endlessly colourful, endlessly breeding — the hardy livebearer that hooked half the hobby on its first tank.
Will it live with a Guppy?
We compare each fish against your guppy on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Adolf's Cory✅ CompatiblePeaceful · 5.5 cm · Medium care · 22–26 °C (72–79 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Adolf's Cory in a shoal of 6+ or it gets stressed and nippy.
- Agassiz's Corydoras✅ CompatiblePeaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Blackline Rasbora✅ CompatiblePeaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Blackline Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Blood Red Tiger Pleco✅ CompatiblePeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Bloodfin Tetra✅ CompatiblePeaceful · 5.5 cm · Easy care · 18–28 °C (64–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Keep Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Butterfly Hillstream Loach✅ CompatiblePeaceful · 6 cm · Hard care · 18–24 °C (64–75 °F)
- Compatible on the things that matter: shared water near 22–24 °C, workable temperaments, and no predator-and-prey size gap.
- Celebes Rainbowfish✅ CompatiblePeaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Celebes Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Corydoras Catfish✅ CompatiblePeaceful · 6.5 cm · Easy care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Corydoras Catfish in a shoal of 6+ or it gets stressed and nippy.
- Diamond Tetra✅ CompatiblePeaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
- Duplicareus Corydoras✅ CompatiblePeaceful · 5.5 cm · Medium care · 23–27 °C (73–81 °F)
- Both are peaceful, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
- Keep Duplicareus Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Elegant Cory✅ CompatiblePeaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Elegant Cory in a shoal of 6+ or it gets stressed and nippy.
- False Julii Corydoras✅ CompatiblePeaceful · 6 cm · Easy care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep False Julii Corydoras in a shoal of 6+ or it gets stressed and nippy.
- German Blue Ram✅ CompatiblePeaceful · 6 cm · Hard care · 27–30 °C (81–86 °F)
- Compatible on the things that matter: shared water near 27–28 °C, workable temperaments, and no predator-and-prey size gap.
- Glass Bloodfin Tetra✅ CompatiblePeaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Hillstream Loach✅ CompatiblePeaceful · 6 cm · Hard care · 20–24 °C (68–75 °F)
- Both are peaceful, and their water overlaps around 22–24 °C — no size, zone or temperament conflicts.
- Narcissus II Cory✅ CompatiblePeaceful · 5.5 cm · Medium care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Narcissus II Cory in a shoal of 6+ or it gets stressed and nippy.
- Neon Dwarf Rainbowfish✅ CompatiblePeaceful · 6 cm · Easy care · 23–27 °C (73–81 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Neon Dwarf Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Panda Loach✅ CompatiblePeaceful · 6 cm · Hard care · 18–23 °C (64–73 °F)
- Both are peaceful, and their water overlaps around 22–23 °C — no size, zone or temperament conflicts.
- Pearl Danio✅ CompatiblePeaceful · 6 cm · Easy care · 20–25 °C (68–77 °F)
- Compatible on the things that matter: shared water near 22–25 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the top of the tank — offer enough cover so they aren't always in each other's space.
- Keep Pearl Danio in a shoal of 6+ or it gets stressed and nippy.
- Platy✅ CompatiblePeaceful · 6 cm · Easy care · 21–28 °C (70–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Rust Corydoras✅ CompatiblePeaceful · 5.5 cm · Easy care · 23–27 °C (73–81 °F)
- Compatible on the things that matter: shared water near 23–27 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Rust Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Slate Corydoras✅ CompatiblePeaceful · 6 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Slate Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Spotfin Corydoras✅ CompatiblePeaceful · 6.5 cm · Easy care · 22–26 °C (72–79 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Spotfin Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Sterbai Corydoras✅ CompatiblePeaceful · 6.5 cm · Medium care · 24–30 °C (75–86 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Sterbai Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Ash Lipped Apisto⚠️ With cautionSemi-aggressive · 7 cm · Hard care · 24–29 °C (75–84 °F)
- Expect Ash Lipped Apisto to harass Guppy at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Banded Dwarf Cichlid⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 24–30 °C (75–86 °F)
- Expect Banded Dwarf Cichlid to harass Guppy at times; give dense cover and watch them at feeding.
- Betta⚠️ With cautionSemi-aggressive · 6.5 cm · Easy care · 24–28 °C (75–82 °F)
- Betta is semi-aggressive and may chase or nip the smaller Guppy — plant heavily and break up sight lines.
- Black Ruby Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 22–26 °C (72–79 °F)
- Black Ruby Barb and Guppy are close in size, but the semi-aggressive one tends to dominate — add guppy in a group to spread the pressure.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Black Ruby Barb in a shoal of 6+ or it gets stressed and nippy.
- Black Skirt Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Expect Black Skirt Tetra to harass Guppy at times; give dense cover and watch them at feeding.
- Keep Black Skirt Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bleeding Heart Tetra⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 23–28 °C (73–82 °F)
- Bleeding Heart Tetra and Guppy are close in size, but the semi-aggressive one tends to dominate — add guppy in a group to spread the pressure.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Bleeding Heart Tetra in a shoal of 6+ or it gets stressed and nippy.
- Colombian Tetra⚠️ With cautionSemi-aggressive · 6.5 cm · Easy care · 24–28 °C (75–82 °F)
- Colombian Tetra is semi-aggressive and may chase or nip the smaller Guppy — plant heavily and break up sight lines.
- Your 75 L tank is below the ~114 L this pairing really wants — crowding raises aggression.
- Keep Colombian Tetra in a shoal of 6+ or it gets stressed and nippy.
- Desert Goby⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
- Expect Desert Goby to harass Guppy at times; give dense cover and watch them at feeding.
- Dwarf Chain Loach⚠️ With cautionPeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Dwarf Chain Loach in a shoal of 6+ or it gets stressed and nippy.
- Eastern Betta⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
- Eastern Betta and Guppy are close in size, but the semi-aggressive one tends to dominate — add guppy in a group to spread the pressure.
- GloFish Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 21–28 °C (70–82 °F)
- GloFish Tetra and Guppy are close in size, but the semi-aggressive one tends to dominate — add guppy in a group to spread the pressure.
- Keep GloFish Tetra in a shoal of 6+ or it gets stressed and nippy.
- Odessa Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Odessa Barb and Guppy are close in size, but the semi-aggressive one tends to dominate — add guppy in a group to spread the pressure.
- Keep Odessa Barb in a shoal of 6+ or it gets stressed and nippy.
- Peaceful Betta⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
- Expect Peaceful Betta to harass Guppy at times; give dense cover and watch them at feeding.
- Samurai Gourami⚠️ With cautionPeaceful · 6 cm · Hard care · 24–28 °C (75–82 °F)
- Different pH ranges (6.8–7.8 vs 4–6.5); doable if you sit in the shared band, but not ideal long-term.
- Water hardness preferences differ (Guppy 8–12 vs Samurai Gourami 0–5 dGH).
- Smaragd Betta⚠️ With cautionAggressive · 6 cm · Medium care · 23–28 °C (73–82 °F)
- Smaragd Betta is aggressive and may chase or nip the smaller Guppy — plant heavily and break up sight lines.
- Three-striped Dwarf Cichlid⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 23–29 °C (73–84 °F)
- Expect Three-striped Dwarf Cichlid to harass Guppy at times; give dense cover and watch them at feeding.
- Alligator Gar⛔ Not recommendedAggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
- Guppy is bite-sized to a 250 cm predatory alligator gar — it will be eaten.
- Alligator Gar is aggressive and may chase or nip the smaller Guppy — plant heavily and break up sight lines.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Clown Knifefish⛔ Not recommendedAggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
- Size gap is too large (90 vs 6 cm): Clown Knifefish will treat Guppy as food.
- Expect Clown Knifefish to harass Guppy at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Fire Eel⛔ Not recommendedSemi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
- Fire Eel (100 cm) is big enough to swallow the 6 cm Guppy whole.
- Fire Eel is semi-aggressive and may chase or nip the smaller Guppy — plant heavily and break up sight lines.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Koi⛔ Not recommendedPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Guppy is bite-sized to a 90 cm koi — it will be eaten.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Redtail Catfish⛔ Not recommendedAggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
- Redtail Catfish (120 cm) is big enough to swallow the 6 cm Guppy whole.
- Redtail Catfish clearly outsizes Guppy and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Spotted Gar⛔ Not recommendedAggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
- Guppy is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
- Spotted Gar is aggressive and may chase or nip the smaller Guppy — plant heavily and break up sight lines.
- Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Wels Catfish (300 cm) is big enough to swallow the 6 cm Guppy whole.
- Expect Wels Catfish to harass Guppy at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Wolf Cichlid⛔ Not recommendedAggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
- Size gap is too large (72 vs 6 cm): Wolf Cichlid will treat Guppy as food.
- Wolf Cichlid clearly outsizes Guppy and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Guppy care specs
- Care level
- Easy
- Breeding
- Easy
- Max size
- 6 cm (2.4 in)
- Min tank size
- 38 L (10 gal)
- Temperature
- 22–28 °C (72–82 °F)
- pH
- 6.8–7.8
- Hardness
- 8–12 dGH
- Lifespan
- 2–3 years
- Diet
- Omnivore
- Swim level
- Top
- Group size
- 3+ (shoaling)
- Family
- Poeciliidae
- Origin
- Northeast South America and the Caribbean (introduced worldwide)
What is a Guppy?
The guppy (Poecilia reticulata) is arguably the most popular freshwater aquarium fish in the world, and for good reason. Hardy, peaceful, vividly coloured and effortlessly bred, it has been the entry point into the hobby for generations of fishkeepers. Males grow to around 3–4 cm (1.2–1.6 in) and carry spectacular, fan-like tails in virtually every colour combination imaginable. Females are noticeably larger — up to 6 cm (2.4 in) — and considerably plainer, with a fuller, rounder body that swells visibly when gravid.
Guppies belong to the family Poeciliidae, the livebearers, which means females give birth to fully formed, free-swimming young rather than scattering eggs. This trait, combined with their low care demands, makes them equally at home in a community tank, a species-only breeding setup, or a child’s first aquarium. The common nickname “millionfish” is only a slight exaggeration.
Where do Guppies come from?
Wild guppies originate from northeast South America and the Caribbean — Venezuela, Trinidad, Barbados and surrounding areas — where they inhabit shallow, warm, slow-moving freshwater streams, pools, ditches and even brackish coastal margins. These waters are typically warm year-round, slightly alkaline to neutral, and moderately hard due to limestone-influenced substrates.
Guppies are now found on every inhabited continent, introduced both deliberately as mosquito-control agents (they eat larvae voraciously) and accidentally through the aquarium trade. The fish sold in shops today are the product of decades of selective breeding and bear little resemblance to the subtle, small-tailed wild type — but their core environmental preferences remain the same.
What size tank does a Guppy need?
The recommended minimum is 38 litres (10 gallons). While guppies are small, they are active, surface-oriented swimmers that need horizontal swimming space, and — critically — they breed prolifically. A tank smaller than 38 L fills up with fry very quickly, and the resulting crowding drives up ammonia and stress.
For a small group of three or more (the recommended minimum), 38 L is a workable starting point. A 60–80 L (15–20 gal) tank gives you far more management headroom, lets you run a community with compatible companions, and buffers water parameters more stably. Keep the tank covered: guppies are surprisingly capable jumpers, especially males in pursuit.
Because they are top-level fish, prioritise a tank that is longer than it is tall. Strong flow from the filter can batter male tails and tire fish out; use a sponge filter or a spray bar to diffuse the output.
What water parameters do Guppies need?
- Temperature: 22–28 °C (72–82 °F). Guppies tolerate a wider band than many tropicals, but aim for a stable mid-range around 24–26 °C (75–79 °F) for everyday keeping. Cooler end suits slow growth; warmer end accelerates breeding and metabolism.
- pH: 6.8–7.8. Neutral to mildly alkaline suits them best. Strongly acidic water below 6.5 causes stress over time.
- Hardness: 8–12 dGH. Guppies are one of the few commonly kept species that genuinely prefer moderately hard water. Very soft setups can suppress colour, weaken finnage and shorten lifespan.
Stability is the overriding rule. Cycle the tank fully before adding fish, and keep up with regular partial water changes — 20–30% weekly is a good baseline. Guppies are forgiving of imperfect parameters, but they reward good water management with better colour, longer fins and healthier fry.
What do Guppies eat?
Guppies are omnivores with a broad, opportunistic diet. In the wild they graze on algae, plant matter, small invertebrates, zooplankton and insect larvae. In the aquarium, a quality micro-pellet or fine-grade flake forms a solid staple. Round this out with small frozen or live foods — baby brine shrimp, daphnia, micro-worms and finely chopped bloodworm — to bring out peak colour and encourage breeding condition.
Feed small amounts two to three times a day, no more than fish consume in two to three minutes per session. Guppies are gluttons and will overeat if given the chance; excess food fouls the water quickly in the smaller tanks they’re often kept in. Include some plant-based flake or spirulina occasionally to reflect the vegetable component of their natural diet.
Are Guppies aggressive — and what fish can live with them?
Guppies are peaceful and make excellent community fish. Males do chase each other and pursue females persistently, which is why maintaining a ratio of at least two females per male is strongly recommended — it spreads male attention and prevents any single female from being harassed to exhaustion. In a heavily male-dominated tank, females can be stressed constantly and lose condition.
The main vulnerability guppies bring to a community is those elaborate tails. Any species known to nip fins — tiger barbs, serpae tetras, some large cichlids — will destroy a male guppy’s finnage quickly. Stick to calm, similarly sized companions: small tetras (neons, rummy-nose), corydoras, rasboras, small livebearers and peaceful dwarf species work well. Avoid large, predatory fish; anything big enough to fit a guppy in its mouth eventually will.
For a full list of compatible and incompatible species, see Guppy tank mates.
How do you tell male and female Guppies apart?
Sexual dimorphism in guppies is among the strongest of any common aquarium fish and visible from a young age. Males are smaller (typically 3–4 cm / 1.2–1.6 in), slim-bodied, and carry the spectacular, fan-shaped caudal fin and vivid patterning they’re famous for. The gonopodium — a modified anal fin used for internal fertilisation — is the definitive anatomical marker.
Females are noticeably larger and heavier-bodied, reaching up to 6 cm (2.4 in), with a rounded belly that becomes visibly gravid (dark “gravid spot” near the anal fin) when pregnant, which is most of the time in a mixed group. Their fins are plain and their colouration muted: usually grey or olive with modest iridescence. Juveniles sex out clearly by around 4–6 weeks of age.
How do Guppies breed?
Guppies are livebearers and breeding is essentially automatic in a mixed-sex tank — it will happen whether you plan for it or not. Females store sperm and can produce multiple batches of fry from a single mating, so even a tank with no current males can yield fry for months.
Gestation lasts approximately 21–30 days depending on temperature, with warmer water shortening the cycle. A typical drop produces 20–50 fry, though large females can deliver 100 or more. Fry are immediately free-swimming and capable of feeding on crushed flake and baby brine shrimp from day one. Adults — including the mother — will eat fry if given the chance, so dense planting with fine-leaved species (java moss, hornwort) or a breeding box is essential if you want to raise a significant portion of the drop.
Because guppies breed so readily, controlling population is the real challenge. Decide before mixing sexes whether you want fry, and plan accordingly. Separating males and females, or keeping a single-sex group, is the simplest approach if you don’t.
What are common Guppy diseases?
Guppies are resilient, but a few conditions appear regularly.
Fin rot (frayed, disintegrating fin edges) is almost always a water-quality problem — elevated ammonia or nitrite, or a dirty, overcrowded tank. Improve the water and the condition usually arrests on its own in early stages.
Ich (white spot) causes fine white grains across the body and fins. It is triggered by temperature stress or the introduction of infected fish, and spreads quickly in a tank. Quarantining all new fish for 2–4 weeks before adding them to the main tank is the single most effective preventive measure.
Wasting disease / “Guppy disease” — a colloquial term covering a syndrome of clamped fins, curved spine and progressive wasting, often linked to Tetrahymena or poor inbreeding in cheap farmed stock. Source guppies from reputable breeders and quarantine all new arrivals.
Velvet (a dusty gold or rust sheen) and fungal infections (white fluffy patches) are less common but appear in tanks with poor water quality or fish under chronic stress.
Health note: symptoms often overlap between diseases, and misidentification leads to the wrong treatment. Before medicating, confirm your diagnosis against a reputable veterinary or fish-health resource. Correcting water conditions and removing stressors should always be the first step.
How long do Guppies live?
With good care, guppies live 2–3 years. This is shorter than many aquarium species, partly because of their fast metabolism and rapid reproductive cycle. Warmer temperatures accelerate growth and breeding but also compress the lifespan; fish kept at the cooler end of their range tend to live somewhat longer.
Inbreeding is a real factor in guppy longevity — mass-produced store fish often carry genetic weaknesses that shorten their lives regardless of care. Purchasing from specialist breeders or refreshing a colony with unrelated stock every generation or two helps maintain vitality. A guppy kept in clean, stable, appropriately hard water with a varied diet and uncrowded conditions will reliably reach the upper end of that 2–3 year window in full colour.
Frequently asked questions
Will guppies breed in my tank?
Almost certainly. Guppies are prolific livebearers — a mixed group produces fry every few weeks. Keep more females than males (about 2:1) to spread male attention, and expect a population if you don't separate them.
Do guppies prefer hard water?
Yes. Guppies do best in slightly hard, alkaline water (pH 6.8–7.8, 8–12 dGH). Very soft, acidic setups suit them less well.
What you need to keep a guppy
The baseline is a heated, filtered 38 L+ tank: a reliable heater to hold 22–28 °C (72–82 °F), a gentle filter that won't batter a guppy in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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