How Do Guppy Fish Reproduce?

Ameera Mills
By Ameera Mills. Updated: August 25, 2019
How Do Guppy Fish Reproduce?

A guppy fish, also known as a millionfish or rainbow fish (Poecilia reticulata), is a species native to South America. Nowadays, however, you can find guppies all around the world. The reason for their popularity among aquarist fans is that they are very easy to care for. They are known to be able to live in both seawater and freshwater tanks.

The reproduction of a guppy fish is, however, somewhat complicated. This procreation can be especially intricate among people with little experience looking after this species species. For this reason, here at AnimalWised, we have chosen to discuss how guppy fish reproduce. We will also be looking at your role in this reproduction, and how to care for newborn guppies.

You may also be interested in: How Do Butterflies Reproduce?


  1. How does a guppy get pregnant?
  2. Is my guppy pregnant?
  3. Is my guppy in labor?
  4. How to take care of fry?
  5. How to raise guppy fry responsibally?

How does a guppy get pregnant?

Guppy fish are popular, not only for their easy care, but also because of their incredible easiness when it comes to reproduction. This easy reproduction can however become a problem, specifically when it comes to irresponsible breeding specifically because guppies tend to overpopulate. This overpopulation can result in more expensive care; the need for a bigger tank and more guppy mouths to feed.

A guppy is ovoviviparous, this means that, contrary to most fish, it does not spawn eggs. Fry (baby guppies) are hatched while still in their mother, being born more developed than most fish. They sometimes even appear as “miniature adults”. During mating, the male chases and harasses the female, who will hide from him among the plants and objects of the aquarium. When she allows him to approach, or is distracted, the male inserts his anal fin, thereby releasing his sperm. This is a fast action which often goes unnoticed by us humans.

A female guppy then stores the sperm. Once she is fertilized, her gestation period lasts between twenty-eight and thirty-one days before birthing her fry. The most interesting part about this entire process is that female guppies can store male sperm for an incredibly long time, sometimes even up to 10 months. In addition, they can sometimes give birth to several broods without having necessarily mated again.

Is my guppy pregnant?

Even if having missed the mating ritual, noticing if your female guppy is pregnant is quite simple. The signs of a pregnant guppy are concrete. It is very important to pay attention to the signs of a pregnant guppy in order to care for them accordingly.

One of the main signs of a pregnant guppy is that they get visibly fatter over a couple of weeks. When the guppy is pregnant with eggs, you will notice a dark spot on her abdomen, which is called a "gravid spot"; this point will darken once the eggs are fertilized.

In addition, many females lose their appetite and become nervous and restless. It is also for pregnant female guppies to rub themselves against aquarium objects, such as; plants or the glass itself.

If you notice that your female guppy is pregnant it is important to provide her with a stress free environment. If she becomes over-stressed it can result in a spontaneous miscarriage. Avoid hitting the aquarium tank glass and be sure to separate the guppy from other incompatible fish species in the tank.

How Do Guppy Fish Reproduce? - Is my guppy pregnant?

Is my guppy in labor?

Although fry delivery is somewhat simple for a guppy, it can also prove to be risky for the mother and her babies. If there are other fish in the tank, they can eat the newborns. For this reason it is very important that if your guppy is giving birth, you know what to do. Her gestation period lasts around 28 days. If you do not know when mating took place, do not worry, noticing when a guppy is in labor is easy to identify.

A couple of days previous to her giving birth you will notice that her abdomen will become more swollen. It will lose its round shape and appear more square. The point of gravity, which darkens through gestation, will have gotten bigger. You might also notice a couple of dark spots in this area, these spots are the eyes of the unborn guppies.

Other signs include inappetence, as well as nervous behavior. Her contractions will appear as small tremors in the female's body, and this is completely normal during delivery. Seeing a female guppy giving birth is, without a doubt, quite a unique process.

If the female guppy is in an aquarium with other species or her own, we suggest moving her to a breeding aquarium, especially if you believe she is about to give birth. By doing this, you will avoid her newborn babies being eaten.

A fry litter can be made up of 100 individual babies. It can sometimes even take a female guppy three days to give birth. Once these fry babies are born, it is important to transfer the mother back to her original tank. If you leave the mother in the tank with the fry, there is a risk that she might eat them.

How Do Guppy Fish Reproduce? - Is my guppy in labor?

How to take care of fry?

From the moment they are born, fry are completely independent, so taking care of them is not very difficult. After three months they take on complete maturity. Before this happens, we recommend keeping them in the breeding aquarium away from other mature fish that might eat them.

Keep the tank water at a temperature of 25 degrees Celsius and change it weekly. Add an abundance of plants to the tank, as well as a protected sponge filter that will not accidentally suck in the small fry.

Feed the young crushed food, between two and three times a day. You will feed them the same way you do with the adults. Deposit the food on the water surface for the fry to eat themselves.

If necessary. remove any sick or dead fish from the tank as soon as you detect any. This is important in order to avoid infecting the others fry fish.

How Do Guppy Fish Reproduce? - How to take care of fry?

How to raise guppy fry responsibally?

Indiscriminate reproduction and ignorance to the importance of natural mating rituals, is one of the main problems when it comes to the reproduction of this species. Many people take advantage of the fecundity of these fish. Irresponsible breeders force reproduction with assiduity, regardless of the conditions of the aquarium, or the high rate of mortality that comes with lack of care.

In addition, the search for certain combinations of guppy colors, has contributed to the weakening of the species genetic load. This irresponsible cross-breeding results in weak specimens with a low-life expectancy.

Many people breed this species without changing the tank according to the necessary size. In order to avoid over-populating a tank, we recommend adopting only females, or only males. Separate the males and females into two different tanks. You can also consider having them in the same tank with other species. These other species will slow down the pace of the mating ritual.

If you want to read similar articles to How Do Guppy Fish Reproduce?, we recommend you visit our Gestation category.

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Jen Liles
"A guppy is oviparous, this means that, contrary to most fish, it does not spawn eggs." The definition of Oviparous is "lays eggs" these animals give live birth.
Administrador AnimalWised
Hi Jen,

You are correct. This was a typo which should have been ‘ovoviviparous’. The typo has been corrected and the statement clarified. Thank you so much for pointing it out!
I wonder if this species is an oviparous or viviparous? Bcause ur description is most likely a viviparous species.
Help me to learn more about guppie fish
Administrador AnimalWised
Hi Sachin
You’re welcome to take a look at our article about guppy fish:
Fish compatible with guppies

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How Do Guppy Fish Reproduce?