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How Long Does It Take For Baby Guppies To Grow? (With Pictures)

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By Lindsey Stanton

young and adult guppy

Did you just get your hands on some guppy fry? Or maybe you already have guppies, and they just decided to spawn and have children. Now you might be wondering how long it takes for guppies to grow and how big they will get.

So, how long does it take for baby guppies to grow? Generally speaking, you can count on a guppy being born at around ¼ inch in length and growing to around 2 inches in length at the most. It takes about 6 months for a baby guppy to grow from ¼ inch to 2 inches, so they grow at a rate of roughly 0.3 inches per month.

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Guppy Fish Size, Growth Rate, & Growth Stages

Your average male guppy is going to grow to be around 2 inches in length at the very most. Once the guppy reaches this size, growth will stop. They are not very large fish.

Guppy fish, the fry, are born at about ¼ inch in length, so in terms of the growth rate, the calculation is pretty simple. It takes a guppy about 6 months to reach its adult size of 2 inches, so you can divide those 2 inches by 6 months.

Realistically, a guppy will grow by about 0.3 inches per month, give or take, so they do grow fairly slowly. There are various stages of guppy growth, which we are going to cover right now.

The 5 Growth Stages

1. Birth

newborn guppies
Image Credit: Maria Sidelnikova, Shutterstock

Guppies are livebearers, which means that they give birth to live fish, not to eggs. The guppy fry is born at roughly ¼ inch in length.

They look a little deformed for the first few hours but will quickly gain their natural shape, and they start swimming as soon as they are born.

2. Juvenile

juvenile guppies
Image Credit: Tio Gian, Shutterstock

Until the guppy is about 2 months of age, it remains in the juvenile state. This is a really important stage where a lot of growth takes place, and it is important to provide them with adequate food and living conditions during this stage.

At the end of the first 3 months, the guppy should be around ¾ inches in length.

3. Young Guppy

young guppy close up
Image Credit: livingpitty, Shutterstock

The next 4 months of the guppy’s life is the young guppy stage. This is when guppies should be sexually mature, and this is where the rest of their growth will occur, from ¾ inches to 2 inches in length.

4. Adult Guppy

red scarlet guppy
Image Credit: Pavaphon Supanantananont, Shutterstock,

Within 6 months of the guppy being born, it should be fully sexually mature and about 2 inches in length. You can expect a guppy to live for about 2 years from the day it is born.


How Often Do Guppies Have Babies?

What is pretty insane about guppies, especially the females, is that they can give birth to a whole lot of live fry at once, and they can give birth very often too.

Under the right aquarium and breeding conditions, a female guppy can give birth to a new batch of fry every 30 days, and each time she does, she can give birth to between 20 and 50 guppy fry.

So, if you have males and females in your tank, you can expect new baby guppies to appear roughly once per month.

Image Credit:Toxotes-Hun-Gabor-Horvath, Shutterstock

Do Guppies Eat Their Own Babies?

Yes, this is a problem with guppies, especially the males. The male guppies will eat their own babies, and a whole lot of them too.

Now, do not be scared or disgusted, because this is the norm with many different types of fish out there. For one reason or another, fish, including guppies, often eat their own fry.

Now, this is more common with male guppies than females, but it does still happen with females.

This is why when you are breeding guppies, it is recommended that your remove the male and female parents from the breeding tank so that the guppy fry does not end up getting eaten by the parents. (Breeding traps work well too, more on those here).

How Long Do Guppies Take To Mature?

As we discussed up above in the first section of today’s article, from the day that a guppy is born to when it is a mature adult, including all 4 growth stages, it will take roughly 6 months for a guppy fry to totally mature into an adult guppy.

Seeing as a guppy only lives for 1.5 to 2 years, this can be considered a long time to mature, because if the guppy only lives for 1.5 years, it will have spent a full third of its life simply growing into maturity.

Of course, this growth process can be hastened if you treat the guppies right and provide them with adequate food and living conditions.

guppy fish in aquarium
Image Credit: Piqsels

How To Make Guppy Fry Grow Faster?

Now, in terms of guppy growth rate, there is only so much you can do in order to make them grow faster from fry to adult. The growth rate is pretty set in stone, but there are a few things that you can do in order to make guppy fry grow faster, plus to make them as healthy and strong as possible.

Tips on Rapidly Growing Guppy Fries
  • One of the most important things you can do to ensure rapid and healthy guppy growth is to keep the water at an even 80 degrees Fahrenheit. In other words, you will probably need to get an aquarium heater for the breeding and fry tank. Any hotter or colder than 80 degrees will impede growth.
  • The other thing you can do to ensure fast guppy growth is to feed them high-quality food and to feed them fairly often. High-quality crushed guppy flakes, spirulina, baby brine shrimp, daphnia, and micro worms are all good options to go with here. When they guppy fry are first born, for the first few weeks, using infusoria for feeding is also recommended
  • Of course, providing your guppies with ideal tank conditions, mainly water that is properly filtered, will help to achieve rapid and sustained growth as well.

Do Guppies Die After Giving Birth?

No, this is a myth and it is not true. Guppies do not die after giving birth. Once a female guppy is fully sexually mature, at about 6 months of age, she can continue pumping out up to 50 baby guppies every 30 days until she reaches old age, at 1.5 or 2 years of age, and dies.

Image Credit By: Zucky123, pixabay

General Guppy Breeding Tips

Breeding guppies is really not all that hard at all. Here are some general guppy breeding tips and practices for you to follow for the best breeding results.

Equipment Needed:
  • Select the guppies you want to breed. Generally speaking, you will want at least 2 or 3 female guppies for every male, which makes breeding less stressful for the females.
  • Get a 10 to 20-gallon breeding tank. You do not want to breed guppies in the same tank they live in. Make sure that the filter is sufficient but does not create much water movement (here are 3 good options). Guppies do not want much water movement when breeding.
  • Do not add any substrate to the breeding tank, but you do want to add lots of java moss and spawning moss to provide the guppy fry with hiding places. If they have nowhere to hide from the parent fish, they will get eaten by the parents.
  • While breeding is taking place, the tank water should have a temperature of 78 to 79 degrees Fahrenheit, and now you can put the selected guppies into the breeding tank.
  • Once you have all of this setup, you will notice the guppies doing some dances and getting really close to each other. This means your guppies are breeding. It is going to take between 26 to 31 days for gestation to take place once breeding has occurred, so expect to wait for roughly 1 month before any fish fry are born.
  • Remove both the male and female guppies from the breeding tank once the fry is born, or else the guppy fry will get eaten by the parents.
  • Keep the water between 78 and 80 degrees Fahrenheit for the guppies, make sure to change about 40% of the water per week, and start feeding them small brine shrimp, infusoria, and other fish foods adequate for fry.
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When it comes to breeding guppies, as you can see, the whole process is quite easy and straightforward. Once the guppies are born at ¼ inch in length, you can expect them to grow around 0.3 inches per month for 6 months until they reach maturity and their full adult size of 2 inches.

Featured Image Credit: Aleron Val, Shutterstock

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