Guppy Fish Growth Stages: Fom Fry to Adult Guppies

guppy fry growth stages

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Guppies have a simple life cycle. In this article, we will explore the various growth stages of guppies and provide guidance on caring for them at each stage to ensure they grow into vibrant, healthy, and sizable fish.

How large can guppies grow? Female guppies can reach lengths of up to 2 inches (5 cm), while males can grow up to 1.5 inches (3.8 cm). By adhering to the recommendations outlined in this article, you can expect your guppies to achieve their full size in approximately 5-6 months.

It’s worth noting that guppies are livebearers. This means they do not lay eggs, thus eliminating the larval stage altogether.

The male guppy fertilizes the female, after which the baby guppies develop inside the mother’s body for about 30 days before birth.

Guppy Fish Growth Chart at Different Stages

Stage Age Size Key Characteristics Care Tips
Fry Guppy Birth ~1/4 inch (0.6 mm) Free-swimming; Might appear misshapen initially Provide hiding spots; Feed powdery consistency flake food; Introduce baby brine shrimp; 12-16 hours aquarium light; Frequent water changes
Juvenile Guppy 1 month 1/4 to 3/4 inches (1.2-2 cm) Distinct colors; Visible gravid spots in females; Males’ tails start showing color Feed brine shrimp, bloodworms, high-quality flakes, spirulina, plankton pellets, beef heart
Young Guppy 2 months 1-1.5 inches (2.5 to 3.8 cm) Begin sexual maturation; Males separated from females by some breeders Reduce fat, increase protein and greens; Focus on brine shrimp, spirulina, plankton pellets
Adult Guppy 6 months onwards Females: 1.5-2 inches (4-6 cm)

Males: 1.2-1.6 inches (3-4 cm)

Fully matured; Fins/tails may elongate based on genetics Feed protein-rich flake food; Avoid fatty foods

Fry Guppy

Guppy fry are naturally free-swimming from birth. Immediately after being born, their instinct is to seek shelter. Initially, they might appear slightly misshapen, but within a few hours, their bodies straighten and they become robust enough to start feeding.

Although guppy fry are petite, measuring about 1/4 inch (0.6 mm) in length, they are often seen as prey by adult guppies and larger fish. To protect your fry, consider isolating the pregnant guppy from the community tank or offering plenty of hiding spots like live plants.

While guppy fry can consume the same diet as their parents, ensure flake foods are crushed into a powdery consistency before offering. Introducing live foods, such as baby brine shrimp, can be particularly beneficial. Additionally, the yolk of a hard-boiled egg can significantly aid in their development.

To promote growth, keep the aquarium light on for 12-16 hours daily.

If you’re feeding the fry multiple times daily, frequent water changes become crucial. Some breeders even opt for daily or every-other-day complete water replacements.

By around one month, guppy fry transition into their juvenile stage.


Juvenile Guppy

In the juvenile stage, guppies begin to exhibit distinct colors, making it easier to differentiate between the sexes. Females are generally larger with visible gravid spots, while male tails are smaller and begin to show color. Additionally, the gonopodium in male guppies starts to form.

The juvenile phase is pivotal in a guppy’s life, emphasizing the need for optimal nutrition and water quality. Suitable foods during this stage include brine shrimp, bloodworms, high-quality flakes, spirulina, plankton pellets, and beef heart.

During the juvenile stage, guppies measure between 1/4 and 3/4 inches (1.2 to 2 cm) in length. By approximately 2 months, they begin sexual maturation, transitioning into young adult guppies.


Young Guppy

Young guppies typically become sexually active around 2 months of age. Selective guppy breeders often separate males from females during the juvenile phase. Keeping the males apart from the females can enhance their growth, as their focus remains solely on feeding rather than reproduction.

The dietary needs of young guppies differ slightly from those of guppy fry. It’s advisable to reduce their fat intake and increase their protein and greens. While brine shrimp should remain their primary food source, incorporating spirulina and plankton pellets can aid in achieving richer coloration.

By approximately 6 months of age, guppies mature into adults.


Adult Guppy

By approximately 6 months, guppies mature into adults. The size they attain as adults largely depends on their genetics and environmental conditions. Typically, an adult female guppy can grow to around 1.5-2 inches (4-6 cm).

Their rate of growth either halts or diminishes considerably. The fins and tails of male guppies might elongate further over time, influenced by their genetic makeup.

For vibrant and healthy guppies, a diverse diet is key. Flake food rich in protein should constitute their primary diet. It’s best to avoid fatty foods, as they can be detrimental to their health.



How Long do Guppies Typically Live?

Guppies have a lifespan of about 2-5 years. However, their longevity can vary based on factors like genetics, diet, water quality, and overall care.  By the age of 1.5-2 years, adult guppies often become infertile and are no longer capable of reproduction.


Can Different Guppy Stages be Housed Together?

Guppies, across various growth stages, can coexist in the same aquarium. However, caution is required. Adult guppies might see guppy fry as prey, potentially leading to predation. Juvenile and young guppies generally coexist peacefully. To safeguard fry, providing hiding spots, like dense plants, is beneficial. Separating pregnant females or using breeding boxes can also reduce risks.

How Often Should Guppies be fed at Different Stages?

Guppies’ dietary needs vary across growth stages. Fry require frequent feedings, about 4-5 times daily, due to rapid growth. Juvenile guppies benefit from being fed 2-3 times daily. Adult guppies, with slower metabolic rates, are sufficiently nourished with 1-2 feedings daily. Overfeeding can lead to water contamination, so it’s crucial to offer food in amounts they can consume within a few minutes.

Image of Guppy Fry:

Updated: October 5, 2023
Questions & Answers
    1. avatar

      Hi Darrel. I recommend keeping baby guppies in a breeding or mesh box for up to one week. It would be ideal if you could separate the babies to a new tank, where they can grow. If you don’t have the possibility to run multiple fish tanks, you can release the babies into the main tank after one week, but provide them with hiding space. Add live plants, such as Java moss or Guppy grass so the fry can hide and be safe.
      Before you release the baby guppies into the tank, feed the parents well, so they will not go after the fry. Release all the fry at once, to lower the changes of the parents are eating them.
      If you have a community tank with angelfish or goldfish, you might not want to keep the babies until they get bigger. Angelfish will eat the small babies no matter you feed them or not. Goldfish have a huge mouth, so they are also a danger for the fry.

    1. avatar

      Yes, you can keep guppy fry together with other small fishes, just make sure you provide them with enough cover and hiding spaces through aquarium plants.

  1. Polyniki

    Hello Fabian, thank you for the info! I was wondering, do Guppies change look when they get older? One of my most fertile females, who used to look fat and bright, stopped getting pregnant some months ago and although she was still very active and healthy, recently I noticed that her tail had sunk and she looked as if she had shrinked in size. Also her skin was kind of greyish. Today I found her dead 🙁 I was wondering if this was simply old age? Thank you!

    1. avatar

      When guppies become infertile, it is a sign that they are getting older. It is normal, that guppies that produce lot of fry will get consumed faster. It is also normal that they lose their color when they get older.
      The aging in guppies can happen really fast, is just few weeks. Their organs and immune system will become weaker and eventually will become sick and die.
      I’m almost sure, that your female guppy died due to old age and due to very active reproduction. This is their life cycle, which is normal.
      Though, I recommend to monitor your other guppies, just to eliminate the possibility of any potential disease.

  2. Polyniki

    Thank you for your answer! Actually she was not dead yet. I thought she was because she was laying on the side and her back was bent to the side too, but she was still alive and survived another 24 hours like this, barely swimming (on her side, spine bent to the side). All my other guppy are doing great but I am still concerned if this might have been some disease. I checked your page on common diseases but nothing suits these symptoms. Her belly was not swollen, no signs of infection or injury. Any clues? Thank you!

    1. avatar

      It is really hard to tell from your description if there could be any disease that affects your guppy. I think she has become week due to giving birth so many times.

  3. Hi, am I correct in assuming a tank will easily become over populated if you have both male and female guppies? What do you do to try to limit this if you only have one tank and can’t separate the sexes?

    1. avatar

      Hey Sarah! Keeping male and females guppies together can result in overpopulation. I’ve wrote a guide on how to control guppy population – check out the linked article.
      If you don’t have the possibility to keep males and females separately, I recommend adding a female betta wish to your tank. The betta will hunt down the small fry and your guppy population will be under control. Some fry might get along, but that is ok, because some of the adults will die off sooner or later, so the new guppies will take their place.
      This is not the way I would do it, but for your setup this might be the best option.

  4. Why guppies’bodies are rolling downward when they are swiming and within next 2 days they will die.. Body turns to pale color also

    1. avatar

      I think this is a swim bedder problem which can be caused by ammonia poisoning. Check water parameters, and make sure ammonia and nitrite levels are at 0 ppm.

  5. Hoang Nguyen

    Hi Mr Fabian , i have a question . How old are the male and female guppies? At how many months can they mate with each other, if they mate at a young age, does it affect the quality of their fry?

    1. avatar

      Hi Haong! The sexual maturity in guppies really depends on their growth rate. Guppies can become sexually active at 3-4 months old. The quality of fry are not affected in this case, though the quantity is significantly lower. A young and small female will only produce 4-10 fry. While a 6-8 months old female guppy can drop up to 100 fry.
      If you want to breed guppies, I highly recommend you separate males from females at 5-6 weeks old and you wait until they get at 5-6 months age. At this age you can already see which males and females you want to reproduce and you choose only the best one for reproduction.
      I found out that guppies will grow faster if males and females are separated. Also tank size and food quality is an important factor in their growth rate.

  6. If a 1 month female guppy is in a tank with another 1 month guppy and a 5 month guppy will she get pregnant or is there more time before I have to separate them.

    1. avatar

      Guppies usually reach sexual maturity at around 3-4 months. So there is still time left to separate them.

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