How Do Fish Mate?

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Fish are not mammals, so they naturally are different in many ways to humans. This might lead you to wonder, especially if you’re new to owning a fish and are eager to get some more, “How do fish mate?”

Here are some facts about how fish mate.

how do fish breed

How Do Fish Breed?

Fish breed in a few different ways. Some fish, in fact, bear live young like humans do. For example, a male guppy will fertilize the female fish, and about a month later, the guppy fry *the young, larval fish) will emerge from their mother, fully formed and able to swim as well as seek out their own food immediately after birth.

Most fish, however, reproduce by laying eggs. Some of these egg-laying fish are known as “egg scatters,” so called because they scatter their eggs in various locations as they go, while a male fish follows behind the female and fertilizes the eggs. This can lead to a race around a fish tank, without even taking breaks to eat!

Other fish, known as substrate spawners, will use their saliva to attach the eggs to a surface. Catfish use this form of mating, with the female leaving the eggs behind for the male to fertilize.

Sometimes the male fish makes the saliva bed, such as with bubblenest builders – in which the male fish blows bubbles into a kind of “nest” that floats near the surface of the water, and the female lays her eggs safely inside this nest.

Still, other species of fish will keep the fertilized eggs in their mouths instead of a nest until the fry hatch.

Generally speaking, fish know what they’re doing and can take care of their mating on their own, in a stress-free experience for aquarium owners. Some species require a little extra maintenance, however.

The Betta Fish Reproduction Process

Betta fish are a popular pet to keep in home aquariums, but as you may already know, the male betta fish is notorious for being extra aggressive.

As such, it cannot be kept in the same tank as other betta fish (most of the time), and so betta fish reproduction requires a little more planning, along with a few extra steps.

how do fish breed

Step One

Note that more than 600 eggs can come from a single spawn of betta fish, and a great number are likely to survive fertilization, so you can end up with a lot of fish!

Make sure you have a tank that will support the new family. Also, clear some space on your schedule; the process of breeding the fish and raising the young could take about two months of dedicated care.

Step Two

Prepare your pair of fish – one male, and one female. They should be young fish of about the same size, for maximum mating compatibility.

Male betta fish will breed at their optimal levels while younger than fifteen months old. For now, the fish should live in separate tanks because of their aggression.

Step Three

Set up your breeding tank. It should be between five and ten gallons in volume, and equipped with a removable divider – a very important tool!

Keep the tank at around 80 degrees Fahrenheit, and keep it free of gravel to avoid losing track of fallen eggs.

This is also a good time to begin preparing the live food that betta fry enjoy to eat, such as microworms or vinegar eels.

Step Four

Release the betta fish into the breeding tank, on either side of the divider, so they can see each other and get used to each other for a few days.

If they show signs of trying to attack each other through the divider, separate them and try again later.

If they show signs of interest, such as the male flaring his fins and the female displaying vertical bars on her body, it’s time to breed!

Step Five

When the male betta fish creates a bubble nest for the eggs, remove the divider and allow the male and female to interact.

They will court for a few days, which can get aggressive, so make sure to keep an eye on the fish for injuries or any need to separate them.

Step Six

Finally, the male will get the female under the bubble nest, and the female will produce eggs for the male to place in the nest. Make sure the female does not eat the eggs!

When she’s stopped producing, remove the female betta fish from the breeding tank to keep her safe. Leave the male, however, until the fry can swim around, which will be about three days after they hatch.

When the fry hatch, feed them live food twice per day, gradually switching to frozen and pellet food after a month or so. Be sure to separate the males when they get old enough to fight!

how fish mate


Now that you know about the reproductive habits of fish, no more will you ask, “Do fish mate?” Instead, you’re ready to start your own breeding aquarium!

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