How Long Are Guppies Pregnant For? (Answered and Explained!)

Female guppy gestation period lasts for between 21 and 35 days. The exact length of gestation is largely down to water temperature. The warmer the water, the fewer days the female is pregnant. The speed of baby guppy development inside the female guppy is affected by temperature.

Eating Daphnia
Eating Daphnia

Guppies are one of the world’s most popular freshwater fish. They are colorful, peaceful, and incredibly hardy. They make a great choice for both new fish keepers and experts alike. Another attribute that makes guppies so popular is the ease with which we can all breed them at home.

I first started keeping guppies more than 30 years ago when I was given a 10 gallon set up and a few guppies. I have been completely hooked ever since, keeping and breeding thousands of guppies over the years. I don’t think a day has gone by since then when I didn’t have a tank of guppies in my fish room.

How Long Are Guppies Pregnant For

The length of guppy gestation can vary massively and is dependent on a number of factors, but the main one is water temperature. The warmer the aquarium water, the quicker the babies develop inside the female guppy. Conversely, the colder the water, the longer the pregnancy will last.

The optimum water temperature for the developing baby inside the female is around 76°F (24°C).

Other factors that affect guppy gestation are the size and age of the female guppy, the quality of food she has been fed, and also stress factors in the aquarium. Stressed female guppies may either retain their babies until the stress factors are gone, or they can even reabsorb their babies altogether.



Is It Possible To Speed Up Guppy Gestation?

In theory, we can speed up female guppy gestation by increasing the temperature in the aquarium. If we were to set an aquarium heater to 82°F (28°C), there is a good chance the female guppy will give birth around the 21-day mark.

In my experience, If you try to speed up gestation, there is a greater chance more of the baby guppies will be born deformed. You might get your baby guppies quicker, but you may also end up with fewer healthy babies.



Is It Possible To Slow Down Guppy Gestation?

Much like trying to speed up gestation, if you lower the temperature, perhaps as low as 72°F (22°C), you will find that the guppy holds the babies inside for longer and gestation will take nearer the 35-day mark.

I have also tried lowering the temperature in the aquariums with my pregnant female guppies, and I haven’t found too many negative issues.

With that said, unless you have a good reason to slow down gestation, I would recommend just setting the temperature to about 76°F (24°C).

How Often Can Guppies Have Babies?

Female guppies are baby-producing machines. Theoretically, a female guppy can have a brood of babies up to once every 35 to 40 days which means 10 or 11 broods of babies per year.

Having that many healthy broods can take its toll on female guppies, so be sure to feed them a healthy, balanced diet that includes lots of protein. I have a great article titled What Do Guppies Eat? which includes lots of ideas for feeding guppies a varied diet.

In Conclusion

Female guppies are pregnant for anywhere between 21 and 35 days. The gestation period is dictated by water temperature with the babies being born sooner in warmer water and taking longer in colder water.


About the Author

I’ve been keeping, breeding, and showing tropical fish for nearly 30 years. Over that time I’ve done it all! I’ve had great success and I’ve made some really foolish mistakes (like the time I bought an Asain Walking Catfish). Read more…
Richard James
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