Live bearing aquatic fish give birth to free swimming fry. These tropical fish species are very common in domestic household aquariums, the most popular being guppies and platies. The eggs are fertilized by the male while they are still inside the body of the female fish, where they develop into semi-mature fry within the female's stomach. In live bearing species, the male's anal fin has developed into a reproductive organ, acting as the transmitter of sperm. When the fry are born - through a live birth - they look like miniatures of their mother/father, but without color.
There are some live bearing species where the female fish can store semen from one single mate and use it to fertilize several batches of baby fry in a row. This is why female live bearers sometimes give birth in aquariums where they are kept without any males. |
Tropical fish species that bury their eggs tend to be natively found in climates where drought is very common. During the extremely wet seasons where water levels are high, the fish will bury their eggs deep within the mud. These eggs will stay within the mud until there is a drought, typically a few weeks later. When a new rainy season begins, the increasing water levels will trigger the hatching of the eggs and the fry will emerge from within the mud. Egg buriers will not safeguard their eggs or young, typically because the parents are either dead after the drought or have swam too far away from the hatching grounds.
If you want to breed egg burying species in your aquarium, you must simulate a dry season and a subsequent rainy season. The Aquatic Community specifically details how to do this method of breeding: |