The guppy degenerates after three generations of inbreeding, because the original genes of inbreeding guppy will become weaker and weaker. When they reproduce to the third generation, the genes will basically disappear completely, so when guppies inbreed to the third generation, they will degenerate. Small fish produced by genetic degradation will be smaller in size, and the characteristics of guppy will become obscure or even disappear. Some small guppies may also be sickly or die young.

1. Choose parent fish: In order for guppies to reproduce good offspring, breeders need to choose suitable parent fish for mating. When choosing parent fish, we should first pay attention to whether they are close relatives. The offspring of guppies bred by close relatives will have genetic degradation. Secondly, we should pay attention to the appearance characteristics, and choose guppies with similar characteristics, so that the genes of offspring will be more obvious. Finally, observe whether the parent fish's body is strong and its shape is complete.

2. Reproduction: After guppy estrus, males will constantly chase females, and if females accept their pursuit, they will cooperate with them to mate. After successful mating, the eggs will develop in the female fish for a period of time, and after the eggs develop into small fish, they will begin to produce. Because guppies are oviparous, their production time will be relatively longer, so breeders need to observe carefully to avoid dystocia.