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Can Guppies Have Babies Without a Male?

Having worked with fish most of my life, I have a strong desire to help others to be successful in the hobby.

Beautiful gold (blond) wild type guppies.

Beautiful gold (blond) wild type guppies.

Can a Female Guppy Get Pregnant Without Mating With a Male?

Although it's not possible for a female guppy to get pregnant without a male, it can appear that she did. Research has shown that a female guppy can hold a male guppy's sperm for 10 months or possibly longer. This may give the appearance that a female guppy is pregnant without being in the presence of a male.

Do Fish Get Pregnant?

Some fish do indeed get pregnant. The egg develops into a young fish inside the female and the fish are free-swimming when they are born. Fish that get pregnant and give birth to live young are known as "livebearers."

Some commonly kept aquarium fish that are livebearers are guppies, mollies, platies, swordtails, and Endlers. The young fry of Goodeids are born with trophotaenia, an umbilical cord-like structure attached to them when they are born.

How Can You Tell the Difference Between Male and Female Guppies?

Years ago, it used to be easy to tell which guppies were males and which ones were female. The male ones were the pretty ones and the female ones were the plain ones.

This isn't exactly true today. Modern guppy breeders have recently produced female guppies which are nearly as pretty as the males making the process of male/female guppy identification just a little bit more difficult. To make things even more difficult, on occasion, a male may be produced that looks nearly identical to a female to the untrained eye.

The best way to identify an adult male guppy is to look for the presence of a gonopodium. The gonopodium is a modified anal fin which is longer and thinner than that than the anal fin of a female guppy. Other differences between male and female guppies are:

Coloration

While it is true that there are some beautiful female guppies available in the hobby today, the males are still the prettier of the two sexes. Male guppies tend to have brighter colors than do female guppies.

Fin Size

Males tend to have more showy fins than do female guppies. The caudal fin and dorsal fins are usually larger and longer.

Body Shape and Size

Female guppies tend to be larger and heavier than male guppies.

Gravid Spot

Female guppies usually have a gravid spot. This is a dark coloration on the underside of the guppy. The gravid spot gets darker when the female guppy is pregnant and grows as the fry inside her grow. The gravid spot will be lighter in color once she has dropped her fry.

Pregnant gold (blond) guppy showing gravid spot.  The gravid spot is darker on a normal colored guppy.

Pregnant gold (blond) guppy showing gravid spot. The gravid spot is darker on a normal colored guppy.

How Do You Know If Your Guppy Is Pregnant?

When an adult female guppy mates with a male guppy, the female is usually in a state of pregnancy of one stage or another for many months. When a female guppy starts to show signs that she is pregnant, the gravid spot on the underside of her body will get darker. This gravid spot will get larger as the fry inside her grow. You may even see the tiny eyes of the small fry through the female's skin when you look at the gravid spot.

Just before dropping fry (around 28 days), the female will look "boxy" as her abdomen gets somewhat squared edges at the front of her body. While guppies usually give birth around 28 days, they may take longer depending on water temperature or if they feel the conditions are not ideal for giving birth.

If a female guppy gets fat and there is no change in the gravid spot, it could be a sign of a serious illness known as Dropsy, which is usually the result of internal organs producing excess fluids as they are shutting down.

Do Guppies Eat Their Babies?

Baby guppies are known as guppy fry. Guppies don't have any real maternal instincts. Young fry are simply looked at as another form of food. Guppies and other aquarium fish will eat the baby guppies if given the opportunity.

Providing lots of hiding places or separating the adult guppies from the fry will greatly increase the odds of the fry surviving to adulthood. Female guppies may also be placed in a breeder box to help protect the newly born fry from being eaten once they are born.

These baby guppies (guppy fry) are about 1/4" long and are able to search for and consume food on their own.

These baby guppies (guppy fry) are about 1/4" long and are able to search for and consume food on their own.

Caring for Baby Guppies

When the fry are first born, they have a small yolk sac attached to their stomachs. This provides the first nutrients to the baby fish for a couple of hours after it's born. The young fry will usually stay near the bottom of the tank until the yolk sac is absorbed. Once the yolk sac is gone the fry will start to swim about the tank in search of food.

What to Feed Young Guppy Fry

If the aquarium is well-established, young guppy fry can find some of the food it needs in the aquarium already. Algae and small microscopic organisms all help to provide nutrients for the young fry. Young guppy fry also enjoys being fed live foods such as baby brine shrimp, daphnia, vinegar eels or micro worms.

Crushed fish food flakes also provide a nice meal for the small guppy fry. The addition of a very small amount of boiled egg yoke can also provide some extra protein. Use egg yoke very sparingly as it can dirty a tank quickly. Commercially prepared foods specifically developed for feeding young fry are also available for purchase.

How Often Do You Feed Guppy Fry?

For rapid growth, young guppies should be fed very small amounts of food often, ideally 5-8 times a day. If that's not possible feeding them twice a day will keep them healthy in a well-established aquarium.

The Great Aspects of Breeding Guppies

Guppies are a fun fish to keep and are easy to take care of. Breeding them is as simple as putting a female guppy in the same tank as a male guppy.

If your female guppy is pregnant and you don't know which male bred with her, you may be in for a real treat as you never know what the baby guppies are going to look like when they grow to adulthood. It's likely that the results of whatever cross may have resulted from the mating won't show up until the second generation of fish is produced.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Questions & Answers

Question: Will my neon tetras eat my guppy fry?

Answer: Yes, Neon Tetras will eat guppy fry.

© 2019 Marty Andersen