You can choose between numerous Guppy fish variations, differencing in the shape of the body as well as the color of the fish. The most common colors are red, green and blue. Guppy variations include:

Veil tail guppy, Lace tail guppy, Lyre tail guppy, Flag tail guppy, Bottom and Double sword tail guppy, Long fin guppy, Fantail guppy, Red tail guppy, Triangle tail guppy, Rounded guppy, Fancy guppy, Tuxedo guppy, Glass guppy, Grass guppy, Mosaic guppy, King Cobra guppy, Snakeskin guppy and Peacock guppy.

Guppies are often kept in community aquariums since they are so peaceful. They do however prefer to be kept in species aquariums, since other fish occasionally assault them by nipping their long fins. When several Guppies are kept together they will form a beautiful school.

Guppies are often bred for their natural color, so over the years the domestic guppy has grown weaker. As a result, guppies will sometimes die after 2-3 days. A guppy may not survive a sudden increase or drop in temperature.

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.

In aquarium:
Occasionally male guppies may behave aggressively towards each other, engaging in fin-nipping and other bullying behavior. Guppies live in complex social networks, choosing social partners and remembering them.

Males have longer, more colorful fins and are smaller than females, which tend to be dull colored. However, the most definitive feature in males is the genitalia – a stick-like modified anal fin.

Source by John Rivera