How fish reproduce: Simple explanation!


Fish can have young in two basic ways, depending on fertilization occurs inside or outside the female's body. We will pay special attention to the reproduction of fish in aquariums and the reproduction of fish for children, which we will exemplify in the clownfish, a fish that has achieved notoriety thanks to children's films Finding Nemo Y Looking for Dori.

Discover below in this article from Animal Expert how fish reproduce:

Oviparous fish

We begin the explanation of how fish reproduce by talking about those oviparous species. These have a external fertilization, that is, the female lays eggs that are fertilized by the male outside her body. These eggs can be deposited in the bottom to be denser, they can float, they can stick to the rocks or algae, or they can be protected in the mouth or in other parts of the body such as the gill chambers. They can also build nests with different materials.

Fish that defend their eggs develop territorial behaviors. Since these eggs can be eaten by predators easily, oviparous fish must lay a large amount, to ensure survival. Bream, trout, tuna, puffer fish, carp or sea bass belong to this group.

Viviparous fish

In this case, to explain how fish reproduce we must understand that we are facing a fertilizationinternal. The males fertilize the eggs that the female carries inside. The female stops the live young, called fry, born completely formed. This type of reproduction increases the chances of survival of the offspring. Some sharks belong to this group.

Ovoviviparous fish

Reproduction of this type also implies a internal fertilization. Females can store sperm to lay eggs without the presence of the male. He performs rituals to attract her. She, after intercourse, carries the eggs in her body. The young mature within the mothers and the eggs hatch or are expelled abroad. The tiger shark, the white or the bull reproduce in this way.

Finally, around how fish reproduce, it is interesting to know that some migrate to reproduce. Thus, the salmon live in the sea and at the end of their life they trace the rivers to spawn. Are anadromous fish. Instead, eels inhabit rivers and, once ready to reproduce, descend to the sea where they spawn. They belong to the group of catadromous fish.

The reproduction of fish in the aquarium

If we want to increase the family in our aquarium we must take into account the following considerations:

  • Obviously, we must be clear about how the fish in our aquarium reproduce.
  • It is important to know that some fish will present sexual dimorphism, that is, males and females have different colors or sizes, which helps to differentiate them.
  • Other fish are going to be hermaphrodites, they can behave as males or as females interchangeably, they can reach sexual maturity as females and become males or vice versa.
  • Depending on the reproductive characteristics of our fish, we must arrange the space. For example, if they are fish that spawn on rocks, they should have them at their disposal.
  • You have to count on that in some cases you will have to separate the fry newborns, because their parents or the other fish could eat them.
  • Likewise, it is important that we reproduce the ideal conditions of their habitat. The temperature, pH, cleanliness and oxygenation of the water or food must be suitable.
  • Having a group of fish favors the success of reproduction.
  • The feeding It must be enough. Beware of overfeeding, as it could make us think that a female is pregnant. We will also have to take special care of the feeding of the fry.
  • We must pay close attention to our aquarium since some females may have arrived fertilized, as is the case with guppies.

The reproduction of fish for children

Finally, in this section we will explain how the fish best known by children, the clown fish popularized by Nemo, reproduce. As we have said, it is essential that we have an aquarium with the ideal characteristics for the species. The clown fish are oviparous and hermaphroditic. They present a ritual of setting and this is more common in the spring.

When it comes to breeding, what happens at about 2 years, the most dominant fish, usually the largest, will be the female. They are going to glue their eggs, orange and in capsule form, on plants, rocks or a simple pot. Shortly before putting them we can see the widest female and both clean their surroundings. The males are in charge of their care and we will see them swimming around them, moving the fins to oxygenate the water. Its color will be modified and they will hatch in 7-10 days, at sunset.

The fry will consume live food and it is good to move them to another well-conditioned aquarium to prevent them from being eaten. The eggs can be moved. This is the stage that presents the greatest difficulty. Low light and power based on rotifer and saline artemia. Both for this aspect and for anyone related to the care of these animals, we should always consult with experts. Finally, if we want to raise these fish at home we must ensure that the specimens they have not been caught in the sea To preserve the environment.

If you want to read more articles similar to How do fish reproduce?, we recommend that you enter our Curiosities section of the animal world.

Discover how fish reproduce

Fish are dioecious animals (their specimens can be separated into males and females) and their sexual reproduction is external, that is, it is carried out without the specimens having physical contact, in fact, the fish do not have copulatory organs.

Thus, the females deposit their eggs so that the males fertilize them. Some fish even build nests for their eggs, while some species protect them inside their mouths.

On the other hand, there are also exceptions: fish with viviparous reproduction (such as sharks), which give birth to fully formed offspring, and ovoviviparous fish, which lay eggs inside the female's belly.

Oviparous fish

Most fish are oviparous and, as such, have a external fertilization. The female lays the eggs and these are fertilized by the male dispersing his sperm in the water. Eggs can be laid at the bottom of the sea, stuck to the rocks or float in the ocean. In some cases, they protect them with parts of their own bodies such as gill chambers or even in the mouth. Further, Some fish take care of the eggs and develop a territorial behavior to protect them

And how do fish reproduce in an aquarium?

If you are thinking of breeding inside your aquarium, there are many previous considerations that you should carry out:

  • Fish choice: better to buy a group, so that they are organized in pairs, of young specimens.
  • Reproduction habits: Each species has a series of habits prior to its reproduction and requires some special conditions, such as a change in diet.
  • Ecosystem: you should worry more than ever about the temperature and pH of your aquarium, also, especially during spawning, try to reduce as much as possible the movement around your aquarium and outside interference.
  • Viviparous fish

    There are also viviparous fish that have an internal fertilization very similar to that of mammals. The males fertilize the female inside. Once the fry they are formed, the female gives birth to live young. Some sharks belong to this group, as is the case with the smooth musola (Mustelus mustelus) or the gray shark.

    Ovoviviparous fish

    The ovoviviparous fish They are a curious mixture of oviparous and viviparous animals. It is also an internal fertilization. After the copulation, the female lays the eggs that remain inside her body. Instead of expelling them, the offspring mature inside the mothers and once the eggs hatch, they go outside. This type of reproduction is very common in sharks. The stingray or white shark reproduce in this way.

    In addition, as a curious fact, females can save some sperm from the first copulation and lay eggs without the presence of the male in the following laying.

    Hermaphrodite fish

    Many species of fish are hermaphrodites, that is, they have both male and female reproductive organs, and can reach sexual maturity as females and then become male or vice versa, or even change sex several times a day.

    Within this group of hermaphrodite fish are the pale serrano (Serranus tortugarum), which can change their sexual role many times a day, what is known as simultaneous hermaphroditism.

    However, the most common is that the fish present a sequential hermaphroditism and change sex at some stages of their development. That is, they are born with a specific sex and in adulthood change to the other.

    This is the case, for example, of clown fish. In this hermaphrodite species, the largest and most dominant specimen in adulthood becomes a female. Once spawning occurs, it is the males who take care of the eggs.

    Finally, an exceptionally rare case, but recently discovered is that of fish that reproduce asexually. The Amazon Molly Fish (Poecilia Formosa), a species native to Texas and Mexico, fertilizes itself, in the same way as other invertebrate species such as starfish or snail.

    Reproduction in fish migration

    Another of the most interesting issues of fish reproduction is that many species migrate to reproduce. One of the most surprising cases is that of salmon, which are born in fresh waters, spend most of their lives at sea and eventually trace the rivers to spawn. These fish are called anadromous.

    On the contrary, other species such as eels are born in the rivers and when they are ready to reproduce, they migrate and spawn in the sea. Are catadromous fish.

    If you liked this article, you may want to know how fish dream, a very different way of sleeping than humans. To learn more about the marine world, don't miss visiting Aquarium Costa de Almería!

    Did you know that there are hermaphrodite fish?

    Explaining how fish reproduce in the case of hermaphrodites is an interesting and enjoyable process, since Hermaphrodites have no specific sex and can become female or male at will according to the need of mating. This is known as simultaneous hermaphroditism.

    However, there is another type of hermaphroditism in which the fish are males in the first part of their life, and then become females. This is called protramental hermaphroditism, while in the opposite case (first female and then male) it is called protogenic hermaphroditism.

    How fish reproduce: migrations

    Migrations during reproduction are common in many types of fish. These are done alone or as a couple, and the distance traveled varies according to the class of fish and the time of year.

    This they do it to look for the mating site that they consider suitable.

    As you can see, the process of mating, fertilization and reproduction of fish was unknown to us, but certainly exciting.

    How to reproduce fish in an aquarium

    If you like fish and now you are fascinated by their reproductive process, you may like to know if they can reproduce in an aquarium that you have or want to put at home. Well, we tell you what you need.

    • Choose the fish well. It is better to have a group of fish instead of just a couple. Of course, you must ensure that they use the same reproduction system, or, at least, that one of the couples does. However, fish are not animals of a couple, and it will be easier to reproduce if there are several options to choose from.
    • Feeding. Some fish need to adapt their habits before the breeding process, such as feeding. Talk to the vet to explain how to do it.
    • Ecosystem. The temperature and pH of your aquarium is vital for the survival of your present and future fish that may come. Avoid sudden movements around the aquarium and outside interference. Peace of mind is vital to the process.

    This is all we know about how fish reproduce. We hope we have aroused your curiosity about these animals that are more than pet friendly. Are you already thinking about adopting one? Courage, you'll love it!