How do Fish Mate? – 5 Different Reproductive Methods

You need to understand the processes involved in fish reproduction. Ordinarily, many people believe that fishes reproduce sexually.

While that is true, it is not the only method involved in fish reproduction.

So, how do fish have babies aside from sexual reproduction? There are many processes involved – and you will learn more about these in this article.

The Major Reproductive Systems of Fish

The first thing you must understand is the reproductive system of fish. These reproductive systems are part of the anatomy of fishes.

If you understand them, it will be easier to understand how fishes mate.

The reproductive systems include:

  • Ovaries
  • Intromittent organs, which are fins modified to function as reproductive appendages. This would then allow for internal fertilization in the fish.
  • Testes
  • Jellylike eggs that are internally fertilized

Types of Fish Reproduction Strategies

This is one of the most important sections of this article. It has a lot to do with how do fish reproduce. So, read on to find out the different reproduction types that play a role in fish reproduction.

1.      Oviparity

Oviparity is also called Egg Laying. It refers to the process of reproducing fish by the internal development of the fertilized eggs.

Therefore, Oviparity has to do with the internal fertilization of the eggs in the female fish. The female fish also needs to shed the newly developing embryos/zygotes.

However, the fish reproduction process wouldn’t be complete until the male fish fertilizes the egg.

For this to happen, the male fish needs to have an intromittent organ that would be used to deliver sperm into the genital opening of the female fish.

2.      Ovoviviparity

Ovoviparity is another reproductive strategy in fishes. In this case, the method of reproduction is also internal.

How do fish mate in this case?

This fish reproduction process involves the reproduction of young fish inside an egg in the parent’s body.

The only difference here is that Ovoviviparous fishes do not receive further nourishment/nutrition from the mother. Instead, the young depends on the food reserve inside the yolk for its development.

3.      Viviparity

This is the last of the fish reproduction strategies. Viviparity has to do with the fertilization and development of young that also receives nourishment whilst in the womb.

There are two different types of Viviparity. They are Hemotrophic and Histotrophic.

For the Histotrophic fish, the fertilization is done inside the mother’s body. However, the young consume other tissues, such as zygotes and ova.

On the other hand, Hemotrophic fish are the ones where the embryo develops in the oviduct of the parent (male or female). The embryo also receives nutrients from the parent.

Unusual Ways of Fish Reproduction

Do fish lay eggs and it ends there?

Well, the trio of Oviparity, Ovoviviparity, and Viviparity are not the only fish reproduction methods.

There are some unusual ways of fish reproduction that we will like you to know. They are:

1.      Unisex

Have you been wondering about how do fish have sex? Well, they mate by reproducing embryos themselves.

This type of fish reproduction is called Unisex. In this case,the female fish single-handedly reproduces the embryo.

Even though the female fish mates with the male, it doesn’t necessarily need the sperm to reproduce.

Also, the embryo or young reproduced in this way is also female – the same as the mother.

2.      Hermaphrodites

This is also another unusual method of fish reproduction. Hermaphrodites are those fishes which possess both female and male reproductive organs.

It is also possible for a male fish to alternate to a female and vice versa. This usually happens when there is no female or male available.

Worthy of mention is that irrespective of the reproductive organ switching, the Hermaphrodites still need a fish of the opposite sex to reproduce.

When do Fish Mate?

The age, size, and species of the fish play an important role in the mating of the fish.

Ideally, early spring and late winter are the best time to find specimens of fishes to breed in your aquarium.

How often do Fish Mate?

It is one thing to consider how do fish mate and it is another to be sure of the duration it takes the fish to mate.

The cycle of reproduction tends to differ by the fish and the time of the year. For example, some bony fishes can spawn many times in a year.

Also, some fishes tend to only reproduce once during their lifetime.

How can I Breed Fish in My Aquarium?

Taking care of and breeding fish in your aquarium may not be the easiest job in the world, but you can be successful at it if you do the right thing.

Here are some tips to start with

1.      Choose the Breeding Pairs

The breeding pairs play an important role in the selection of the right parents for your fish. You want to choose both a male and a female fish.

You also want to consider other important factors that can influence the breeding, such as:

  • Scales
  • Compatibility of the fishes
  • Swimming patterns
  • Clear eyes

2.      Set up the Breeding Tank

The breeding tank also affects the breeding of fish in your aquarium. So, you want to make sure that the tank is well set up before you start breeding your fish.

Some of the most important things to keep in mind are:

  • Heaters and filters
  • A tank size that can accommodate up to 20 gallons of water
  • Substrate
  • A tank with a glass partition for separating the female and male fish
  • Live or plastic plants
  • Consider a separate tank for breeding and raising the fry
  • Use castles and stones as decorations
  • Maintain a water level of 10F above the usual temperature to make it convenient for the fish to survive.

How does Goldfish Mate?

You will know that your male goldfish is mating when it starts chasing the female goldfish until the female goldfish releases her eggs.

It is only after the female goldfish releases her eggs that the male goldfish will fertilize the eggs with his milt.


The reproduction of most fishes is done sexually via the fusion of the eggs produced from the ovaries of the female and the sperm from the male.

Yet, that is not all there is to how fishes mate, because the other methods we talked about (Ovoviviparity, Viviparity, Oviparity, and Hermaphrodite) are also a part of the fish reproduction process.

So, which other fish reproduction method do you know and how is it done?

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