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Do Guppies Eat Their Fry? Exploring the Cannibalistic Nature of Guppies

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Guppies are one of the most popular freshwater fish species in the world. They are known for their vibrant colors, peaceful nature, and ease of care. However, one question that many guppy owners have is whether or not guppies eat their fry.

The answer to this question is not straightforward. While guppies are known to be cannibalistic, whether or not they will eat their own fry depends on a variety of factors. In this article, we will explore the reasons why guppies may or may not eat their fry, as well as provide some tips on how to prevent this behavior from occurring.

Guppy Reproduction

Guppies are known for their prolific breeding habits. They are livebearers, which means that they give birth to live young instead of laying eggs. Male guppies have a modified anal fin called a gonopodium, which they use to fertilize the female’s eggs. The female guppy can store sperm for several months and can give birth to multiple batches of fry from a single mating.

Female guppies are capable of giving birth to as many as 200 fry at a time, although the average is closer to 30-60. The gestation period for guppies is typically around 4 weeks, although this can vary depending on factors such as water temperature and the health of the mother.

Poecilia reticulata and Poecilia sphenops baby fish

Guppy fry are born fully formed and can swim and feed on their own almost immediately. However, they are still vulnerable to predation and can be cannibalized by adult guppies if they are not separated from the rest of the population. It is common for guppy breeders to use breeding traps or separate tanks to protect the fry until they are large enough to fend for themselves.

Overall, guppy reproduction is a fascinating process that has been studied extensively by scientists and hobbyists alike. By understanding the basics of guppy breeding, fish keepers can ensure the health and well-being of their populations and even selectively breed for desirable traits.

Fry Development

After the female guppy gives birth, the fry will be very small and fragile. They will need special care and attention to ensure their survival. The fry will typically be around 4-6mm in length and will require a specific diet to thrive.

Within the first few days, the fry will start to develop their digestive system and will begin to consume small amounts of food. They will need to be fed multiple times a day with small amounts of food to prevent overfeeding and ensure they are getting the proper nutrients.

As the fry continue to grow, they will start to develop their coloration and markings. This process can take several weeks, and the fry may not fully develop their adult coloration until they are several months old.

It is important to note that not all fry will survive to adulthood. Factors such as water quality, temperature, and diet can all impact the survival rate of the fry. Additionally, some adult guppies may prey on their own fry, so it is important to separate the fry from the adults to ensure their safety.

Overall, fry development is a delicate process that requires careful attention and monitoring. With proper care and feeding, the fry can grow into healthy adult guppies.

Why Guppies Eat Their Fry

Many fish species, including guppies, exhibit cannibalistic behavior towards their own offspring. This may seem counterintuitive, but there are several reasons why guppies eat their fry.

Firstly, guppies are known to have a high reproductive rate, with females capable of producing up to 200 fry at a time. This can lead to overcrowding in the tank, which can cause stress and disease among the fish. By eating their own offspring, guppies can regulate their population and maintain a healthy environment.

Secondly, guppies are opportunistic feeders and will eat anything that fits in their mouth. Fry are small and vulnerable, making them an easy target for adult guppies. In the wild, this behavior helps to ensure that only the fittest offspring survive and pass on their genes.

Finally, guppies may eat their fry as a source of nutrients. Fry are rich in protein and other essential nutrients, which can help adult guppies to grow and maintain their health.

While it may seem cruel, cannibalism is a natural behavior for many fish species, including guppies. By eating their fry, guppies are able to regulate their population, maintain a healthy environment, and obtain valuable nutrients.

Preventing Fry Cannibalism

One of the biggest concerns for guppy breeders is fry cannibalism. Unfortunately, adult guppies are known to eat their own fry, which can be a frustrating and heartbreaking experience for breeders. However, there are several strategies that can be employed to prevent this behavior and increase the survival rate of guppy fry.

Separating the Fry

One of the most effective ways to prevent fry cannibalism is to separate the fry from the adult guppies. This can be done by using a breeding box or a separate tank for the fry. A breeding box is a small container that can be attached to the side of the main tank, allowing the fry to be safely contained while still being able to receive the benefits of the main tank’s filtration system. Alternatively, a separate tank can be set up specifically for the fry, providing a safe and controlled environment for them to grow and develop.

Providing Adequate Hiding Places

Another strategy for preventing fry cannibalism is to provide adequate hiding places for the fry within the main tank. This can be done by adding plants, rocks, or other decorations to the tank that provide cover for the fry. In addition, using a fine mesh net or a sponge filter can also help to protect the fry from the adults.

Feeding the Adults

Ensuring that the adult guppies are well-fed can also help to prevent fry cannibalism. When adult guppies are hungry, they are more likely to eat their own fry. Therefore, it is important to feed the adults a varied and nutritious diet to keep them satisfied and less likely to turn to their own offspring for food.

By employing these strategies, guppy breeders can greatly increase the survival rate of their fry and prevent the heartbreaking experience of fry cannibalism. Separating the fry, providing hiding places, and feeding the adults are all effective ways to prevent this behavior and ensure the continued health and growth of guppy fry.


After conducting extensive research on the topic, it is safe to conclude that guppies do, in fact, eat their fry. While some may argue that this behavior is instinctual and necessary for the survival of the species, it is important for aquarium owners to be aware of this behavior and take steps to prevent it if they wish to keep their fry alive.

One effective way to prevent adult guppies from eating their fry is to provide plenty of hiding places for the fry to escape to, such as plants or decorations in the aquarium. Additionally, separating the fry from the adult guppies in a separate breeding tank can also be an effective way to ensure their survival.

It is important to note that while guppies may eat their fry, this behavior is not always a guarantee. Some guppies may not exhibit this behavior at all, while others may only eat a portion of their fry. Ultimately, it depends on the individual guppy and their behavior.