Like other livebearing aquarium fish, swordtails (Xiphophorus hellerii) give birth to live young, or fry, rather than laying eggs. Although the swordtail's gestation period is 28 days, it may be difficult to determine when she became pregnant.

How many eggs do Swordtails lay?

Swordtails can produce 50 – 100 fry every time and may give birth again four to 6 weeks after the first birth. It may take longer. According to experts, the second birth session can even take up to a half year after the first, and that can take place even without the presence of a mate.

How often do Swordtails have babies?

Swordtail Fish are Livebearers The swordtail belongs to the group of livebearer fishes – scientifically classified as Poecillidae – to which the mosquito fish, the guppies, the mollies and the platies belong. A female swordtail can produce offspring as often as every four weeks.