White guppies and common guppies cross to give birth to white seeds, because white guppies have recessive and dominant genes. When white guppies cross with common guppies, their offspring become guppies with recessive white seeds genes. Although there are recessive genes, they don't show up, so their offspring can't become white guppies. But breeders may get white guppies by mating two guppies with recessive white genes.

The easiest way for breeders to breed white guppies is to mate two white guppies together. In this way, the offspring they produce will definitely be white guppies, and the characteristics and genes of the offspring are obvious.

If the breeder has no male or female fish, the breeder can also choose to breed a white guppy and ordinary guppy. Although the offspring they breed cannot become white guppies, when the offspring continue to mate, they will produce white guppies. Although this can produce white guppies, it will weaken their physique, and compared with ordinary guppies, their adaptability will be worse.