How Do Fish Have Sex?

How Do Fish Have Sex

If you’re staring into your fish bowl or just taking a walk by the canal and wondering if the fish are having sex, then you’re probably right. However, it doesn’t exactly look the way you think it does.

The fact is that different species of fish have sex and reproduce in different ways. While some actually have a physical mating ritual which can be termed as sex, Others require no concrete mating action in order to reproduce.

How Do Fish Have Sex?

The majority of fish do not really have “sex” if they want to reproduce. The most common way they do it is by the female of the species laying eggs, which either float in the water or are clumped together in a nest. The male then fertilizesthese eggs which eventually sink towards the bottom where the eggs can develop and mature.

The basic difference between fish not needing to have sex versus the ones that need to is that the fertilization of the eggs takes place outside the body of the female. The organs of a fish are completely different from that of mammals, which means that the fish also don’t have the same genital body parts as mammals and therefore cannot have sex in the same way.

The fertilization of the eggs has to of course take place, which is duly carried out outside the bodies of the fish. Until the male fish fertilizes the eggs that the female has laid, the reproductive process technically doesn’t begin.

Also, the female fish usually releases hundreds of eggs in one go and neither the male nor the female fish has any control over whether the eggs are successfully fertilized. This is perhaps why so many eggs are released by the female fish at one time.

Related: Facts about Sex

Some Variation

There are some species of fish, however, who have a mating ritual which requires them to fertilize the eggs within the body of the females instead of her laying the eggs in the water first. In these species, the male fish does have an organ which is similar to the mammal penis and has the same function –  that of releasing sperm into the female fish.

These fish do not release the eggs into the water and instead the female fish carries the eggs inside her belly for their development and the eggs are eventually released as larvae when they are close to hatching. Because the female in these species carry the eggs instead of releasing them in the water, they do not carry as many eggs as the other species who release them into the water do.

Live Births

It might surprise you to know that there are also some species of fish such as some sharks and guppies who give live births. This means that when they give birth the baby fish are fully formed and hatched out of their eggs. These species fertilize their eggs internally in a mating ritual which is similar to that of mammals.

Fish Sex: It’s Weirder Than You Think!

Did you ever wonder how fish have sex? Buckle up for a wild journey through the sex lives of everything from lobsters to anglerfish. In this hilarious talk, marine biologist Marah J. Hardt explains why sex in the sea matters, how we humans impact it, and what we can do instead to protect our oceans, and future generations of fish.

Marah received her PhD in marine science from Scripps Institution of Oceanography and is working on solutions for overfishing, climate change, and the coral reef crisis. She is founder and CEO of OceanInk and the Director of Discovery at the Future of Fish. She wrote the book, Sex in the Sea.

Related: Fascinating Facts about Seahorses