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Poecilia reticulata PETERS, 1859


SynonymsTop ↑

Lebistes poecilioides De Filippi, 1861; Girardinus guppii Günther, 1866


Poecilia: from the Greek poikilo, meaning ‘variable, variegated’.

reticulata: from the Latin reticulatus, meaning ‘reticulated, having a network-like pattern’.


Order: Cyprinodontiformes Family: Poeciliidae


Native to northeastern South America and the southern Caribbean with its original range considered to cover Venezuela, Guyana, Suriname, French Guiana plus the islands of Trinidad and Tobago, Barbados, Antigua and Barbuda and the Netherlands Antilles.

Type locality is ‘Guayre River, Caracas, Venezuela’.

Wild examples are relatively rare in the aquarium hobby, most fish being commercially bred.

Introduced or feral populations also exist in around fifty other countries across the globe, including the UK.


An incredibly adaptable species that occurs in almost every imaginable biotope, from high-altitude streams to turbid swamps and ditches.

Some populations also exist in brackish conditions.

However it does tend to thrive best in habitats with lush growths of algae, marginal vegetation and/or aquatic plants.

Maximum Standard Length

2.5″ (6cm)

Aquarium SizeTop ↑

18″ x 12″ x 12″ (45x30x30cm)


Unfussy, though a planted tank with floating vegetation is appreciated.

Strong currents should be avoided.

This is a hard water fish and while it may manage in soft and/or acidic conditions, long-term maintenance should be in moderately hard or harder water.

Water Conditions

Temperature17 – 28 °C

pH7.0 – 8.5

Hardness143 – 536 ppm


Wild fish are primarily insectivorous, but today’s tank-bred fish are far-removed from their ancestors and will accept most foods offered.

Behaviour and CompatibilityTop ↑

A very peaceful fish. Do not keep with fin-nipping species such as tiger barbs, serpae tetras etc. Does well in a quiet community tank with other livebearers, rasboras, corydoras, small loricariids and tetras.

Sexual Dimorphism

In the wild type males are the more colourful sex and have elongated finnage, and this is taken to extremes in the selectively bred aquarium varieties.

The male fish also possesses a gonpodium, which is a modification of the anal fin used in reproduction and is stick-like in appearance.

Females are larger, plumper and generally exhibit dull colouration, although aquarium bred varieties may show some quite intense colouration in the caudal fin.


Very easy. Livebearer. It is advisable to keep several females to each male as males can be quite vigorous in their constant pursuit of females. No real effort needs to be made to breed these fish although a densley planted species tank with lots of floating vegetation is the best way to ensure the survival of the fry.

A pregnant female can be identified by the gravid spot (darkened area) behind her anal fin just behind the belly. Between 5-100 young may be produced from a single female, and gestation takes between 4-6 weeks.

Excess viable sperm can be preserved in the female’s oviduct for a long time.

This means that the females are still able to produce young for 6 months or more if no males are present. Adult fish will eat the young so it is better to remove them after the fry are born to ensure 100% survival. They are incredibly prolific so if you do not want a tank full of fry buy fish of only one sex.

NotesTop ↑

One of the most popular aquarium fish in the world, the guppy is instantly recognisable to most people. There are many aquarium bred varieties of this species available, most have elongated finnage and gaudy colouration. The wild form is seldom seen for sale.

Unfortunately many commercially bred guppies are not very hardy due to inbreeding and over-production and are prone to disease and premature death. We therefore recommend the purchase of quality stock from breeders or society auctions.

P. reticulata has been introduced into many third world countries as a means of malaria control, as these fish feed voraciously on mosquito larvae.


  1. Peters, W. (C. H.), 1859 - Monatsberichte der Königlichen Preussische Akademie des Wissenschaften zu Berlin: 411-413
    Eine neue vom Herrn Jagor im atlantischen Meere gefangene Art der Gattung Leptocephalus, und über einige andere neue Fische des Zoologischen Museums.

6 Responses to “Poecilia reticulata – Guppy (Lebistes poecilioides, Girardinus guppii )”

  • rowland

    Under the “water Conditions” section the minimum temperature of 64°F converts to 17.7°C not 23°C as stated..

  • Hi rowland and thanks for the correction which I’ve now fixed. This profile is a bit of a toe-curler so will be back to improve it properly in a short while.

  • Sverting

    Loosely translated text written by Roman Slaboch (PhD):
    “Cool, fast flowing hillstream flowing out of Cievo del Guácharo grotto was one of the most “decent” habitats. To see the full picture, imagine water full of foams flowing off the washingmachine, or a cesspool-like stream full of decaying filth. Literally, these are habitats of modern guppys (ed. poecillia reticulata). […]
    But for the first time in my life I saw guppys in a streamlet, where the “water” was 2 cm deep with no natiral source whatsoever. The water was coming from an outflow located at the street, where people sometimes pour out dirty water. They were in excellent condition, and males where shining with emerald green […]
    On the same station in maritime town of Santa Fé, where guppys where the most beautifull, the water achieved pH 8,5 and 33,2°C (ed. 91.76°F) with the air temperature 33,6°C (ed. 92.48°F) at day, and thanks to the cool winds from the sea, 21,9°C (ed. 71.42°F) at night. […]
    I couldn’t let myself return to my homeland without some specimen – it would be unforgivable. Thankfully my friend found them in cesspit on the subburbs of La Playon. It was really hard to catch them – in the pit measuring only 60x60cm (ed. 24in.) it would be impossible to maneuver the 100x100cm (ed. 40in.) net. So, we detached the net, took a deap breath, rake the bottom, pick the fish, shake off the feases and.. again. Odiousness! This was the first time I was affraid of infections, even though I was vaccinated with set of injections. Water parameters were typical, pH 8,9, 30,5°C(ed. 87°F), the air temperature was 36,2°C (ed. 97°F).
    I brought back 5 pairs. At first I gave them a 30l (8 gal) tank with sandy bottom and lots of Cabomba. After two days I had 2,3 (ed. pairs); males ond the bottom and females swimming uncoordinatedly failing to avoid any obstructions. Then I remembered their home and put some soap into the water (literally washed my hands in the tank). Conditions changed, and next days I saw males courting females vigourusly.”

    Translated by Me. No one other than SF may use it without my written permission.

  • Sverting

    Oh! And another thing! Wild guppys don’t eat their young. Of course if they are not fed in two days they will prey on small guppys, but normally it’s not the case.
    Eating their young is probably an effect to the careless breeding in order to gain new colour forms.

  • Rey

    Should add into the maintenance section that the species is euryhaline (like the related molly) and can live in fresh, brackish and even salt water.

  • sydnee.hanton

    You recommend keeping this species with Rasboras, Tetras and Corydoras? Guppies do best in very high pH, while Tetras, Corydoras and Rasboras do best in acidic pH. Keeping long finned guppies with nippy Tetras is asking for disaster. Yes, even Neon Tetra and Glowlight Tetra are very nippy. Also, even though Loricariids are South American, the small ones still need a lot of space and will dig up plant life.

    Guppies are also highly active fish, which will stress out a lot of others. For their compatibility I would house them only with Rainbowfish, Danios, Swordtails, Platys, etc. Those are all high pH, livebearers.

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