guppies reproduce only female fish, because they need male fish to mate with female fish to reproduce offspring, and if only female fish can reproduce. However, guppies have a characteristic that they store sperm after mating, so they can produce again without mating once. They are oviparous fish, which take longer to produce than other fish. It takes about 3-4 hours for each production, so it is best for breeders to pay attention to observation when they give birth to avoid dystocia. Although guppy has been produced for a long time, its reproduction frequency and quantity are relatively high, so it is also called "million fish".

Guppies can inbreed because their genes are strong, so the same nest of guppies can reproduce. But breeders should not allow inbreeding too many times, or it may cause genetic degradation.

Under normal circumstances, it is best for breeders not to inbreed for more than 3 generations, otherwise it will not only cause gene degeneration, but also cause the offspring to grow little. Others may have poor physique, thin body, etc., and some will die directly.