Guppy

The guppy (Poecilia reticulata), also known as the millionsfish,[1] is one of the most popular freshwater aquarium fish species in the world. It is a small member of the Poecilidae family (females 4-6 centimetres long, males 2½–3½ centimetres long) and like all other members of the family, is live-bearing.





Taxonomy
Robert John Lechmere Guppy discovered this tiny fish in Trinidad in 1866, and the fish was named Girardinus guppii in his honour by Albert C. L. G. Gunther later that year. However, the fish had previously been described by Wilhelm Peters in 1859 on material collected from South America. Although Girardinus guppii is now considered a junior synonym of Poecilia reticulata, the common name "guppy" still remains.[2] Over time guppies have been given a variety of taxonomic names, although Poecilia reticulata is the name currently considered to be valid.






Distribution
Guppies are native to Trinidad and parts of South America, specifically Antigua and Barbuda, Barbados, Brazil, Guyana, Netherlands Antilles, Trinidad and Tobago, the US Virgin Islands, and Venezuela.[3]
However, guppies have been introduced to many different countries on all continents, except Antarctica. Sometimes this has occurred accidentally, but most often as a means of mosquito control, the hope being that the guppies would eat the mosquito larvae slowing down the spread of malaria. In many cases, these guppies have had a negative impact on native fish faunas.[4]






Ecology and behaviour
Guppies exhibit sexual dimorphism. While wild-type females are grey in body colour, males have splashes, spots, or stripes that can be yellow, orange, blue, or black.
There is a great deal of variety between the populations, many with distinctive coloring or patterning. Those that live in habitats where predators are common tend to be less vividly decorated as a protective measure. Populations that deal with fewer predators are much more colorful. Recent studies suggest that vividly colored males are favored via sexual selection (handicap principle) while natural selection via predation favors subdued tones. As a result, the dominant phenotypes observed within a reproductively isolated community are a function of the relative importance each factor has in a particular environment.
Occasionally male guppies may behave aggressively towards each other, engaging in fin-nipping and other bullying behaviour. Guppies live in complex social networks, choosing social partners and remembering them.[5]
Guppies are a seminal species for evolutionary biologists because predation often varies over small geographic areas. Both historical work and recent studies are summarised in Anne Magurran's Evolutionary Ecology: the Trinidadian Guppy





Reproduction


Guppies are highly prolific livebearers[6]. The gestation period of a guppy is 22-30 days, with an average of 28 days. After the female guppy is inseminated, a dark area near the anus, known as the gravid spot, will enlarge and darken. Guppies prefer water temperatures of about 28 °C (82 °F) for reproduction. The female guppy has drops of between 2-100 fry, typically ranging between 30 and 60. After giving birth, the female is ready for conception again within only a few hours.
The guppy has been successfully hybridised with the molly (poecilia latipinna/velifera), eg male guppy and female molly. However, the hybrids are always males and appear to be infertile.
The guppy has also been hybridised with the Endler's livebearer.

Guppy fry in an aquarium, 1 week

The guppy prefers a hard water aquarium and can withstand levels of salinity up to 150% that of normal sea water.[7], which has led to them being occasionally included in marine tropical community tanks, as well as in freshwater tropical tanks. Guppies are generally peaceful, though nipping behaviour is sometimes exhibited between male guppies or towards other top swimmers like platys and swordtails and occasionally other fish with prominent fins such as angelfish. Its most famous characteristic is its propensity for breeding, and it can breed in both fresh water and marine aquariums.[8]
Guppy breeding by aquarists produces variations in appearance ranging from color consistency to fantails and "spike" swordtails. Selective breeding has created an avid "fancy guppy" collector group, while the "wild" guppy maintains its popularity as one of the hardiest aquarium fish.
Guppy breeding by aquarists produces variations in appearance ranging from color consistency to fantails and "spike" swordtails. Selective breeding has created an avid "fancy guppy" collector group, while the "wild" guppy maintains its popularity as one of the hardiest aquarium fish.
Experienced aquarists breeding their own guppies are aware that the adults will eat their young and, therefore, provide safe zones for the fry. Specially designed livebearer birthing tanks, which can be suspended inside the aquarium, are available from aquatic retailers. These serve the dual purpose of shielding the pregnant female from further attention from the males, and of providing a separate area for the newborn young as protection from being eaten by their mother. Although if a female is put in the breeder box too early or late it will cause her to have a miscarriage.

http://en.wikipedia.org/wiki/Guppy