Guppies (Poecilia reticulata) are livebearers, which means these fish give birth to live, viable, free-swimming young instead of eggs that still need to mature. Understanding how guppies give birth can help aquarium enthusiasts enjoy breeding healthy guppies without stressing the pregnant mother or risking the lives of the young fry.
How Guppies Give Birth
When guppies give birth, the female will "drop" 2-200 baby guppies, called fry, typically in four to six hours. If she is stressed, however, the process to give birth to all the fry can take up to 12 hours. In extreme cases, a female guppy may give birth to just a few fry at a time, with pauses of several hours or days between births, although in most of these cases the young are not viable and die quickly. Typically the fry are delivered one at a time, although they may appear in quick succession with pauses between groups of babies.
The baby guppies are usually born curled into small balls, just as they matured in the female's womb in this compact shape. They will uncurl and begin swimming quickly, however, and newborn guppies often swim upward if they are very healthy. Unhealthy, premature or stillborn young will sink.
When Your Pregnant Guppy Is Ready for Birth
Female guppies can become pregnant when they are just a few weeks old, and if they are not separated from male guppies they can give birth on average once a month for several years. Guppy breeders quickly learn to recognize the signs of a pregnant guppy, including significant weight gain and the darkening of the gravid spot near the anus under the tail. The gestation period for guppies is from 21-30 days (22-26 days is average) depending on the tank's temperature, cleanliness, and the female's health. Near the end of that gestation period, the female will show signs of the impending birth.
Different fish have different personalities, and not every female guppy will show the same symptoms of birthing. Watching for the following signs can help you know when the time for birth is drawing near.
- Boxy, squared-off look to the female's abdomen
- The gravid spot is very dark maroon or black
- She grows still in the tank or seeks a place to hide
- Change in eating habits, such as refusing to eat or spitting food out
- Shivering or shuddering motions during contractions
- Increasingly rapid breathing
When a female guppy shows indications that she is ready to give birth, it can be a good idea to move her to a birthing tank or net inside the normal tank or in a completely separate tank. This will separate her from the other fish in the tank so she does not need to exert herself avoiding from them. Birthing tanks also frequently have partitions that give the fry a safe place to begin swimming - fry are a delicacy to many fish, including the hungry mother.
Helping Guppy Moms and Newborn Guppies
After giving birth, the female guppy should be kept in a quiet tank for at least several hours so she can recover her strength and energy before joining the rest of the fish, and she should be well fed to help her recovery. If the batch of fry was exceptionally large, she may need up to a full day or two to recover sufficiently, but isolating her for longer periods can be too stressful.
Newborn guppies, although they can swim quickly, are at risk in a tank with other fish because they can easily be eaten. Placing a variety of floating plants near the birthing tank or throughout the tank where the fish will live offers the fry a place to hide, and plants can be either real or plastic. Any dead fry should be removed immediately so they do not create excessive waste or toxins in the tank, and the remaining fry should be fed an appropriate diet for fast, strong growth. The tank should also be kept at an appropriate temperature, usually between 72-79 degrees Fahrenheit, and it should be cleaned regularly to prevent the buildup of waste.
Knowing how guppies give birth and how to care for both the pregnant female and the newborn fry will help guppy enthusiasts enjoy regular births of strong, healthy fish they can appreciate for years.