Breeding guppies is not difficult at all, in fact, getting them not to breed is the hard part.

The first step in breeding a male and a female guppy is determining which is which. This is not difficult at all since male and female guppies are easy to distinguish.

Male guppies are smaller then females, but they are much more colourful and their fins and tails are longer as well. Males also have a gonopodium which is a modified fin which is used to impregnate the female.

Females on the other hand are much larger then males and less colourful. They also have a gravid spot which is a dark spot near their vent. When she becomes pregnant this area will expand and the babies will be seen through it.

All that is needed to get a male and female guppy to mate is to put them in the same aquarium. It is best if there is a small aquarium (5-10 gallons), filled with plants. Feeding your guppies well on live food will also condition them. Although all these extras are not needed, buy supplying a comfortable environment their young will be larger and there will be more of them.

Guppies will eat their own young if they are small enough and plants will give the young fish a hiding place from their parents. Not all guppies will try to eat their young though. If they are well fed fish you should not have a problem, but separating the parents from the fry is often a good idea.

Guppies become mature at about 3 to 5 months of age, at which time they can start breeding. Females can deliver a new batch of 10-100 young every month as well, which can mean a population explosion of guppies. It may be necessary to cull your young fish.

Females can also hold onto any unused sperm form the male for several months so even if you have a female separated from a male for weeks she can still give birth.