How many babies do guppies have?

Guppies are one of the most popular freshwater fish in America; they can sometimes be called rainbowfish, or even millionfish due to their prolific breeding nature. A pregnant guppy can birth to anything between 5 to 30 fry, but the exact number will differ from fish to fish. As a member of the Poeciliidae family, all guppies are livebearing fish. This means that they don’t lay eggs - they give birth to live young. 

But how many babies do guppies have, exactly? Read on to find out more about these fascinating fish and their breeding cycle!

How many babies do guppies have?

The exact number of babies - or fry, as they’re known - that a guppy can have will vary depending on both the female guppy and the environment of the tank she’s in. Female guppies generally tend to spawn anything between 2 and 200 fry over the span of 4 to 6 hours.

On average, a female guppy will tend to give birth to between 20 to 40 fry; the record number of fry born in a single brood is a whopping 244! The guppy’s environment can influence how many fry she gives birth to or how long the gestation period lasts. Factors such as cleanliness, the temperature of the water, and the female’s individual health come into play to determine when or for how long a guppy will give birth.

Under extreme cases, a female guppy could give birth over a longer period of time, with fry being born a few at a time. In healthy fish the baby guppies tend to be born one after another, although this may be in quick succession with pauses between some groups of young.

If the female guppy is stressed the birthing process will take much longer - potentially up to 12 hours. In very extreme cases the female may give birth in batches, taking pauses every few hours or even days. These young don’t tend to be healthy or viable and are likely to die. The female may become stressed with trying to avoid other fish in the tank; it’s generally good practice to separate her into her own birthing tank so that she can give birth in peace.

How are baby guppies born?

Unusually, guppies are what’s known as livebearing fish. This means that they in fact give birth to live free-swimming offspring instead of eggs. Guppies are notorious for being prolific breeders, and the eggs are fertilized inside the female, where she will incubate them until they reach maturity.

Baby guppies are born curled up in little balls. The moment they’re in the water, they uncurl and spring into life. Healthy fry will tend to swim for the surface, whereas unhealthy, stillborn, or premature fry will sink to the bottom of the tank.

Baby guppies will have something called a yolk sac attached to them. This is how they got their nutrition before they were born - this is rapidly absorbed by the individual fish before they swim to find other things to eat.

Pregnant guppies should generally be moved to their own individual birthing tank, and not only so as to reduce the stress the mother has to endure. Guppies have cannibalistic tendencies, and unless the pregnant mother is separated from other guppies, the fry will get eaten by any other fish in the tank - sometimes even the mother herself!

Prolific breeders

Guppies breed like rabbits. These little fish are notoriously prolific breeders because they reach maturity so quickly. A guppy fry will reach sexual maturity within 1 to 3 months, and female guppies can become pregnant within a few weeks of their birth. 

Unless you separate the female guppies from the males, they will pretty much be pregnant for most of their lifespan. A female guppy will give birth to around 1500 young on average during her lifetime! Unless you actively separate your female guppies from your male guppies, on average the females will give birth to new fry once a month for several years.

The female doesn’t even need to have been around male guppies for a long period of time before getting pregnant. In fact, she can store a male guppy’s sperm for anything between 8 months and even up to a year. A female guppy can have up to 8 broods from a single mating! This process is known as superfetation, and ensures that guppies are able to reproduce rapidly.

How can I tell if my guppy is pregnant?

Depending on the coloring of your guppy, it should be fairly easy to tell whether she’s pregnant or not. The main giveaway will be the darkening of her gravid spot, or gravid patch as it is sometimes known. This is the area where the abdomen meets the tail underneath the fish, and will gradually darken throughout the stages of pregnancy.

At first, this will show as a yellowish discoloration, gradually darkening through brown, orange, and eventually a dark maroon or black color if the birth is imminent. This darkening is the eyes of the baby guppies developing - the orange tinge is their jelly-like eyes! Other factors which can indicate pregnancy are significant weight gain, as well as the female’s abdomen taking on a squared-off, boxy appearance.

The gestation period of a female guppy will differ from breed to breed, but on average tends to be between 22 to 26 days. It could be anything from 21 days up to 30 days, but this will be entirely determined by the breed of your guppy, as well as her immediate environment and whether she’s stressed or not.

Determining whether your pregnant guppy is about to give birth will differ from fish to fish. This tends to be shown in a change of behavior, either in feeding habits or with the female guppy trying to hide from the other fish in the tank. Or perhaps the female guppy will start shivering or shuddering, or have an increase in rapid breathing.

Once you’re sure that your female guppy is about to give birth, you will need to separate her from the other fish in your tank. You will also need to ensure that the baby fry are separated from the mother in the event that she might try to eat them - though some species of guppy are more likely to do this than others.