Poecilia Reticulata (guppy)

Poecilia reticulata which is most known as the guppy belongs to the Poeciliidae family. Other common names are ”millions fish” and ”rainbow fish”. In the past, guppies have changed their scientific names such as Lebistes reticulatus, Girardinus guppii by several scientists.
The species is native to Central America (Barbados, Trinidad, and Tobago e.t.c), and to South America (Venezuela, Brazil e.t.c). Furthermore, Poecilia reticulata has been introduced to other continents accidentally or for the reduction of the mosquito population. Because of the resilience of the species, they exist in a wide range of habitats, but in general, guppies occur in freshwater and brackish water streams in coastal areas, which they contain more salt and minerals from other habitats.
Because of the selective breeding of these fishes, there are many colors and caudal fin variations. For the exact reason, the domestic varieties that we see in aquariums are different from their ancestors, the wild Poecilia Reticulata.
The species have sexual dimorphism, with the males being more colorful with bigger caudal fins than females. Females almost always have a gray color, rounded body, with some variations having a more colorful caudal fin. Another considerable difference between the two genders is their size, with the males being smaller than females. Guppies have an average size of 2 inches (5cm). Male guppies, like the rest of the Poeciliidae family, have their anal fins modified to the rod-shaped male’s reproductive organ, the gonopodium. In females, behind the anal fin, there is the ”gravid spot”, which expands and darkens in color when female is close to delivery. The species have a lifespan of 2 years, yet if cared properly, guppies can live up to 5 years.
This peaceful, social fish is an excellent choice for beginners because of their hardiness and stunning, various colors. They like to be kept in groups, in a ratio of 1 male per 2 female, as they get stressed from the persistent chasing by male guppies throughout reproduction. They are also suited for community tanks with peaceful species with a similar size and water chemistry of guppies. Some compatible species with Poecilia reticulata are other species of the Poeciliidae family like platies and mollies, e.t.c. On the contrary, aggressive species or fish that like nibbling the tails of fish due to their big caudal fin such as tiger barbs, are not compatible.
Because of the natural habitat of Poecilia reticulata, they should be kept in hard alkaline water. Although guppies can survive in a wide range of water parameters, a pH between 7.0-7.5, with a temperature between 21-25 Celsius, and hardness between 100-150 mg/l, suits the species. Another interesting fact is that guppies because of their natural habitat can thrive in brackish water as well as in a freshwater aquarium.
Because most livebearers are active species and inhibit in highly oxygenated waters, consume more oxygen and produce more carbon dioxide, with the result that they need a reasonable space in the aquarium. An aquarium of 22 liters could be enough for a group of 3 guppies (1 gallon per 1 inch of a fish rule), but keep in mind that such a small aquarium is not suitable for any fish because it will be difficult to keep the water parameters stable. Not to mention that poeciliids are prolific breeders, and they need fairly big aquariums for that. An aquarium with pure 40 liters of water is much more suitable and easy to maintain for only 3-5 guppies without their offspring.
Plants are essential for livebearers as they provide shelter for stressed fish and their offspring, providing chemical and physical conditions for the growth of microorganisms that can be eaten by the poeciliids.
Guppies are omnivorous and can eat prepared food and small live-foods such as brine shrimp, micro-worms, daphnia, white worms, tubifex. In nature, their diet consists of algae, organic detritus, diatoms, mosquito larvae, e.t.c.
Guppies are very easy to breed, you only need both sexes. Like the rest of the poeciliid family, they give birth to live fry. They reproduce better at a temperature between 23-25 Celcius. The male chases the female, and when the female guppy is ready, she stays immobile for a few seconds until the male fertilizes her. The action is repeated continuously by the male guppy. It’s interesting that females can store sperm inside their body for months and get pregnant, without a male. The gestation period lasts 4-6 weeks and affected by environmental factors, diet, age and size of the female guppy. As I mentioned earlier, the gravid spot gets bigger and darker when the female is close to delivery.
The female Poecilia reticulata gives birth to 20-100 fry in one brood. The brood is affected by the age and size of the female guppy. The offspring reach their sexual maturity the third month of their life. Keep in mind that guppies are cannibals and eat their young. A planted tank may help the babies to survive. You can also place the offspring in breeding traps as well as in nursery tanks for their safety.

Guppy Multi Colored Fish in a Tropical Acquarium


  1. Earl Schneider and Dr. Leon f. Whitney 1957, The Complete Guide
    to tropical fishes
  2. David Alderton 2005, 2008, Encyclopedia of aquarium and pond fish, Published in the United States by DK Publishing, ISBN 978-0-7566-3678-4
  3. Wilfred L. Whitern 1983, Livebearers, ISBN 0876665180
  4. Poecilia reticulata. Retrieved from https://www.seriouslyfish.com/species/poecilia-reticulata/
  5. Poecilia reticulata. Retrieved from https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=165903#null

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