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How Many Babies Do Guppies Have? (Monthly & During A Lifetime)

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Breeding guppies is relatively easy. All you have to do is mix a male and a female. However, it also comes with plenty of questions. I remember wondering how many babies guppies can have, as I didn’t want my tank to get crowded. Fortunately, as years passed, I gained some experience in this field.

Guppies can have between 5 to 80 babies at one time. They are fertile for approximately 57 months, meaning that they can deliver between 300 to 4500 fry in a lifetime. However, keeping guppies in a stressful environment with inappropriate water conditions will result in fewer fry.

As we move forward, I will elaborate on how many babies guppies can deliver and what steps you should take to ensure they reproduce efficiently. I will also discuss the survival rate of guppy fry and whether the fish can actually reach menopause.

Still curious? Feel free to check my complete guide on pregnant guppy fish. There, I discussed how to care for pregnant guppies, how long they remain pregnant, how to identify signs of pregnancy, and a lot more.

How Many Babies Do Guppies Have?

People call guppies ‘million fish’ because they are very fertile. Livebearers give birth every 28 days and tend to add anywhere between 5 and 80 babies to the tank each month.[1]

Guppies follow a similar pattern. If you’re rearing the species for the first time, this is what you need to know about their numbers:

1. The Monthly Volume Of Guppy Fry

Guppy Breeding is easy. Once you place male and female fish in the same environment, they will mate. You don’t have to coerce them. In fact, some newcomers have to stop their guppies from breeding.

However, you cannot always predict the number of fry they will produce in a given session. In most cases, you can expect anywhere between 5 to 80 babies at one time.

The birthing process tends to last a maximum of 12 hours. Though, for some fish, labor will exceed 24 hours. Such cases are rare.

2. The Frequency In Which Guppies Get Pregnant

The frequency of births matters because it affects the number of babies a guppy will produce during its lifetime. The shorter the gestation period, the more babies the guppy can produce in a given year.

Guppies have a gestation period of 21 to 31 days. Thirty days is the average, but it isn’t uncommon for these creatures to give birth within 21 days. Once they give birth, they can get pregnant again in the following week.

You can take steps to decrease the gestation period. The most effective tool is the temperature. Guppies can thrive in tanks with temperatures as low as 72 degrees F. But you can expedite the pregnancy by raising the temperature one or two degrees each day.

You can also feed the creatures foods rich in protein. Cold-water and poor feeding habits will increase the gestation period, reducing the number of babies the guppy can produce during its lifetime.

3. The Total Volume Of Fry During A Lifetime

A guppy can produce roughly 2000 fry during its lifetime. If the creature gives birth to 50 babies each month without fail and sticks around for five years, the guppy’s total volume is closer to 3000 fry.

However, this assumes that the conditions are ideal, which is not always the case. Guppies can produce fewer babies than you expect, and for a variety of reasons, including:

  • Bad Genetics

Some livebearers have genetic anomalies that won’t permit them to produce more than one or two fry each month. Some of them will even die while giving birth.

You primarily see this issue when there isn’t sufficient diversification, mostly known as inbreeding. In this case, you cannot do anything to improve their output. Your best option is to sell your guppies and start over.

  • Old Age

How old are your fish? If they are giving birth for the first time, their output shouldn’t concern you. Young guppies release very few fry when they give birth for the first time.

However, with each passing month, the number of babies produced will grow. You should only be concerned if the guppy’s output remains the same or becomes lower as your fish ages.

  • Stressful Environment

Stress can compromise a guppy’s fertility. In some scenarios, they will give birth to fewer babies. In others, they will abort their offspring or reabsorb them.

Either way, the number of fry the guppy can produce during its lifetime will decrease drastically. Common causes of stress include overcrowding, a poor diet, and bullies.

I suggest removing the tankmates to another tank to overcome this issue, including the male guppies. Avoid moving the mother herself. This can cause unnecessary stress and even abortion.

  • Inappropriate Water Conditions

Poor water conditions are a significant source of stress. The wrong parameters and ammonia spikes can delay pregnancy, cause an abortion, or encourage the mother to reabsorb her babies.

As a rule of thumb, these are the ideal water conditions for pregnant guppies:

  1. Temperature: 75–80° F (24-27° C) 
  2. Water pH: 6.9–7.5 
  3. Hardness: 9-10 dGH 
  4. Ammonia and nitrites: 0 ppm 
  5. Nitrates: <20 ppm

To measure the ammonia, nitrates, nitrites, and pH, I personally use the API Water Test Kit (link to Amazon). This bundle is a bit more expensive than average. However, it is highly accurate and lasts for about eight hundred measures.

  • Filial Cannibalism

Some guppies produce plenty of fry each month. Unfortunately, they keep eating their offspring. This behavior is expected, and it is the reason why people separate mothers from their babies once the guppy is going to give birth.

The best way to do that is to use a divider. The tiny holes will allow the fry to escape to the other side of the tank. This method is better than moving the mother guppy to another tank, as she is highly vulnerable at this stage.

How Many Baby Guppies Are Likely To Survive?

Here’s the thing. Just because your guppy gave birth to 50 babies at once doesn’t mean they will all survive. Roughly 20 to 30 percent of guppy fry survive.[2] Factors like food quality and water conditions will shape the survival rate.

What About Sperm Retention?

Sperm retention is an incredible ability found in guppies. When a female guppy mates with a male fish, it can store the sperm to fertilize its eggs without the male. Sperm retention has two significant consequences:[3]

  • First, a female fish can continue giving birth in a tank with no males. This is a problem for aquarists that want to prevent breeding by keeping the males and females in separate tanks.
  • Secondly, a female fish can conceive immediately after giving birth.

If your guppy’s gestation period ended after 21 days, you might assume that it won’t conceive for a few more days or weeks because it needs time to recover.

You may also keep the female in a separate tank to protect the fish from any males that want to mate with it. However, if the fish stored sperm, it can still fall pregnant mere hours after giving birth.

This will increase the number of babies the guppy will produce over its lifetime because it has shorter gaps between pregnancies.

Female guppies can store sperm for six months or longer. This matters because they tend to outlive their male counterparts by at least twelve months.[4] Therefore, a female that stored sperm will continue to give birth even after the male guppy dies.

The sperm retention ability gives you time to find new replacements for the dead males. If the female mates with a male guppy before the stored sperm runs out, it will continue to give birth without delays or interruptions for the rest of its life.

Do Guppies Have Menopause? 

Some guppies do not remain fertile forever. They will eventually enter menopause.[5] But the consequences will vary. People expect menopause to prohibit the fish from giving birth, which can happen.

However, more than likely, the guppy will skip litters, or the breaks in between reproduction will expand. In other words, reproduction will not stop completely.

How Long Are Guppies Fertile? 

Guppies have a life expectancy of three to five years.[6] This is important because they can reach sexual maturity within one to three months.[7] If you have a healthy guppy in a well-maintained aquarium; it will breed for roughly 57 months.

This assumes that the creature will live to a ripe old age of five years. You can expect new babies every month for 57 months.

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Conclusions

On average, guppies can produce between 50 to 60 babies each month. That typically happens in aquariums with proper water conditions and a stress-free environment. Generally, it would help if you aimed for a temperature of 75–80° F (24-27° C) and a pH of 6.9–7.5.

Bear in mind that guppies can reach menopause. During that period, which occurs at the age of 57 months, guppies will produce fewer fry in wider intervals. Also, young guppies that have just reached sexual maturity aren’t likely to deliver the average number of babies.

References

  1. https://injaf.org/aquarium-fish/beginners-guide-to-livebearers/
  2. https://helpusfish.com/1/10/how-do-you-keep-baby-guppies-alive.html
  3. https://www.smithsonianmag.com/smart-news/dead-male-guppies-can-make-babies-94404464/
  4. https://www.nationalgeographic.com/animals/article/sperm-hoarders-why-animals-store-semen
  5. https://www.nbcnews.com/id/wbna10643970
  6. https://www.aquariumsource.com/guppy-fish/
  7. https://petsuppliesauthority.com/how-many-babies-do-guppies-have/