Do Fish Give Birth?


It is known that fish lay eggs, which hatch after a while outside the body of the mother; yet, are there fish that get pregnant and give birth? If you enjoy cultivating fish in aquariums, you will notice that guppy, also known as millionfish and rainbow fish, keep their eggs inside their bodies; when the eggs hatch, the mother gives birth to free-swimming live young fish. The guppy gestation period ranges from 21–30 days; depending on the tank's temperature and cleanliness, and the female's health. Breeders recognize the signs of a pregnant guppy, such as significant weight gain and the appearance of a dark spot near the anus under the tail. After that, the female drops between 2–200 baby guppies, also known as fry, within 4–6 hours, and sometimes 12 hours in extreme cases.

There are other types of aquarium fish that are live-bearers, such as molly, platy, and swordtail. Fish reproduction methods vary, but most types of fish lay eggs. The female fish lays unfertilized eggs in water nests or builds a safe area for them, then the male fertilizes these eggs; that is, the eggs are fertilized and mature outside the mother's body. In this case, you may notice jelly-like floating orbs on the water surface or in your aquarium.

In this case, a problem arises as some fish eat their own spawn or the spawn of other species. As a result, breeders tend to separate fish eggs from adult fish, which may give them a better chance of survival. Breeders may resort to fish hatchery; a place for what is known as artificial breeding, hatching eggs, and rearing young fish through their early stages. The output of a hatchery is normally fry, fingerlings, or juveniles, depending on the fish's life stage/age. These young small fish are then transferred to an on-growing section to reach harvest size.

Can male fish get pregnant and give birth instead of females? Male pregnancy is rare and does not occur in mammals, but this phenomenon occurs in pipefish, seahorse, and seadragons during the mating process. The female transfers dozens or hundreds of its unfertilized eggs to the male's underside, where it fertilizes. The male then carries its fertilized eggs for several weeks until they are born; just like the female kangaroo, which keeps its young in its pouch, except that the male fish does the job.

This cannot be considered a true pregnancy. During a mammalian pregnancy, the placenta allows the female to nourish her progeny in the womb, and get rid of its waste products; the pipefish and seahorse only provide a bag for fish eggs to develop and hatch. However, current research suggests that, in some species with well-developed brood pouches, males do provide nutrients, osmoregulation, and oxygenation to the embryos they carry.


Banner Image Source:

About Us

SCIplanet is a bilingual edutainment science magazine published by the Bibliotheca Alexandrina Planetarium Science Center and developed by the Cultural Outreach Publications Unit ...
Continue reading

Contact Us

P.O. Box 138, Chatby 21526, Alexandria, EGYPT
Tel.: +(203) 4839999
Ext.: 1737–1781

Become a member

© 2024 | Bibliotheca Alexandrina