guppy (Poecilia reticulata) also known as the million fish is a small and colorful aquatic animal of fresh water with tropical temperatures, naturally from rivers and lakes. There are 300 different types of guppy distributed throughout South America.

Guppy macho

Guppy macho


The guppy is a fish with a great variety of colors, and sometimes, it displays many elaborate patterns on its tail fin. They exhibit sexual dimorphism, that is, the differences between males and females are clearly identifiable. The female's tail is small and patterned, while the male's is much longer and has fewer markings.

The female is also larger in size than the male. The size varies but generally the males are between 1,5 - 3,5 cm in length and the females between 3 - 6 cm. In nature they have a life expectancy of about 3 years, which are compensated by a high reproductive quality.


The guppy in captivity is very different from the wild one since through selective breeding they have been able to create different colors, patterns, shapes and sizes of fins.

There are also strains morphologically different from the wild ones. The males and females in many strains are larger and much more luxuriously adorned than the wild ones.


The guppy is a fish native to Antigua and Barbuda, Barbados, Brazil, Guyana, Jamaica, the Netherlands Antilles, Trinidad and Tobago, the US Virgin Islands, and Venezuela.

Sometimes their distribution has occurred accidentally, as they have been used as a method of mosquito control. It was expected to eat mosquito larvae to control malaria but it has been negative and has caused problems for other native fish.

Various studies show that guppies have spread throughout almost all fresh waters close to their natural range, especially in streams near the coasts of continental South America. Guppies are also known to be able to survive in brackish waters, but they are more abundant in pools and large, deep or fast-flowing rivers.


The guppy is an omnivorous fish that feeds on a wide range of organic matter that is available in the water. Eats remains of algae, diatoms, invertebrates, plant fragments, mineral particles, aquatic insect larvae, and other species. In wild species, algae remains are the main food although it varies depending on the habitat. For example, the guppies from the Aripo River consume small invertebrates as their main food, but the guppies from the Tacarigua River consume diatoms and mineral particles.


The guppy naturally has many predators, due to its small size and its coloring that attract too much attention. The main predators are birds like the kingfisher and larger fish like Crenicichla alta, Anablepsoides hartii, and Aequidens pulcher.

When there are high levels of predation, the more colorful guppies have a greater risk of being hunted, so the males evolve to more muted colors, both in the wild and in captivity, and the females also choose the males with less bright colors over the more colorful.


The guppy is a ovovíviparo fish, that is, the female gives birth to live young as she incubates the eggs and they hatch inside. The incubation period is around 30 days.

They have a modified tubular anal fin called the gonopod, located behind the ventral fin from where sperm are transferred to females. The male will make a courtship to attract the female, once she is receptive and will briefly insert the gonopod into the female's genital pore to initiate internal fertilization. Sometimes a furtive mating is performed where the male forces the female and pushes the gonopod into the female's urogenital pore.

Once fertilized, the female is capable of storing spermatoids in her ovaries and gonducts, which can remain useful for up to eight months. Due to this mechanism, the male can obtain offspring even when dead, which influences the reproductive dynamics of wild populations. This is where the popular name of the guppy comes from, "the million fish."

The female gives birth to up to 100 young called fry. At birth they can feed and swim on their own. They also have the ability to sense danger, to avoid being eaten by predators, even older groupies. After a couple of months they will have reached their adult stage.

State of conservation

The guppy is not threatened and is rated Least Concern. They reproduce by the thousands and can store sperm, they are also bred in captivity by humans as pets.

Relationship with humans


The guppy is a very popular animal among humans around the planet, since they are very easy to care for than other species of fish and they are small and very colorful. In captivity they usually live longer than in the wild, ranging from 3 to 5 years.

Disease Control

It was introduced in other countries as a method of mosquito prevention and to control malaria and malaria, since the guppy feeds on mosquito larvae before it begins to fly, but no great results were achieved.

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