Guppies (Poecilia reticulata) breed like rabbits. The frequently give live birth, which has contributed to their popularity in aquarium circles -- both by making the fish readily available and giving breeders a large pool of fish to work with. Several factor contribute to guppies' rapid rate of reproduction.
Guppies rapidly reach maturity. Since guppies give live birth instead of laying eggs, guppy fry (baby fish) are born more developed that most fish. Unlike egg layers, they start life as miniature adults. A guppy can start to reproduce at only 2 to 3 months of age.
Pregancy in Guppies
Guppy physiology and behavior also contribute to their rapid rate of reproduction. Males constantly try to mate with females. On top of this, a single mating can produce multiple batches of offspring -- a characteristic called super-foetation. This combination of frequent mating and super-foetation means female guppies are more or less constantly pregnant as soon as they reach maturity.
Number of Offspring
Once a female guppy is 2 or 3 months old, she tends to start giving birth. A female guppy under optimal conditions can give birth every 30 days -- and each batch of fry can range from 20 to 50 baby guppies. This combination of maturing rapidly, birthing live young and almost constant reproduction means guppies reproduce very rapidly.
When breeding guppies, the biggest concern is the parents. Adult guppies eat baby guppies although, in a densely planted aquarium, at least some of the babies will avoid predation. However, for serious breeding efforts, a pregnant female should be carefully removed to a separate aquarium and returned to the main tank after giving birth. Since guppies reproduce so rapidly, any serious guppy breeder should take tank space into account.
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