Life Stages of Guppy Fish (updated for 2022)

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Guppies are one of the most popular tropical fish in the hobby. They have been kept and selectively bred over decades to give us the astonishing range of colors available today.

I have been keeping, breeding, and showing guppies for nearly 30 years. Over that time I have fallen in love with this wonderful fish. Its life is short but truely fascinating.

Life Stage of a Guppy

Guppies essentially have 4 separate stages in their life. These stages are;

  • Baby (known as fry)
  • Juvenile
  • Young
  • Adult

During each of these stages of a guppy’s life, the fish is doing something different. Guppies are fish that never gets boring to watch and always manage to surprise their keepers.

Baby Guppies

Guppies are livebearing fish. This means the female guppies give birth to live, free-swimming baby fish that are fully independent of their parents from the moment they are born. Baby guppies are usually referred to as fry.

Adult guppies take no parental responsibility for their young. In fact, there is a high probability that the adults will eat the babies, even their own babies, given half a chance. The inbuilt desire to eat their own babies is known as filial cannibalism. I wrote more about it in an article titled Why Do Guppies Eat Their Babies (and how to prevent it)

Guppy babies are small when they are born. Each fish only measures around 1/4″ (0.6 mm) long. When they are first born they are curled up, but they quickly straighten themselves out and start looking for food. Baby guppies usually eat within the first 1 to 2 hours after birth.

Baby guppies are highly vulnerable. I can only assume they are incredibly tasty as every inhabitant of the fish tank seems to want to eat them. We as fishkeepers can either let nature take its course and those that survive to get to grow up into adult fish, or we can give the babies a helping hand to survive the first few days by using a guppy breeder box or adding lots and lots of live plants to give the babies some cover.

As mentioned above, guppy babies will usually start eating after 1 or 2 hours. As the fish are very small, they need equally small food. I tend to feed my baby guppies either crushed up flake food or some live or frozen food like newly hatched Brine Shrimp.

Baby guppies need good quality food that is rich in protein. crumbled egg yolk is a great source of protein for baby guppies and one that I feed to all my newborn guppies. How fast baby guppies grow is largely dependent on what and how often they eat.

Caring for baby guppies is a topic I have written about extensively over the last few years. I recently wrote a short article titled How To Care For Guppy Babies?

Guppies are considered babies for about the first 3 weeks of their life, after which it is generally agreed they become juvenile guppies.

Juvenile Guppies

After around 3 weeks, guppies enter the juvenile stage of their life. During this stage, the guppies begin to develop color and it starts to become clear which guppies are males and which are females.

It is at this stage that some top-end breeders begin separating out the two sexes to reduce the chances of the females becoming pregnant at this young age. Breeders who are breeding for selective traits such as color, size, or fin shape don’t want their females to become pregnant via a random male, they want to select which male she is partnered up to.

Juvenile guppies do not require quite as much protein in their diet, and as such, I personally don’t feed them crumbled egg yolk from this stage onward. However, as the guppies are now larger, they can get larger food items. Once guppies enter the juvenile stage I often introduce bloodworms and mosquito larvae into their diet. The addition of these foods, either live or frozen, helps the juvenile fish grow fast and strong and ensures they will develop bold colors.

At this stage in a guppies’ life, they are usually around 1/2″ to 3/4″ (1.2 to 2 cm) long.

Young Guppies

Between weeks 6 and 8 guppies are considered to be young guppies. Many of the fish show their adult coloration at this stage and it is perfectly possible for female guppies to become pregnant during this stage of their lives.

Anyone hoping to selectively breed individual guppies would want to be removing female fish by this stage in their lives, otherwise, a random male will fertilize the females.

Young guppies like more live or frozen food added to their diet along with good quality flake or pellet food designed for guppies, or at least for tropical fish. In my own guppy breeding room I tend to feed two or three different foods each day, maybe giving the young guppies flake food in the morning, followed by live or frozen food in the afternoon, then a good quality pellet food in the evening.

In my experience, this feeding regime builds strong, colorful guppies.

During this stage in their lives, guppies tend to spend the entire day looking for food, and they will eat as much as you add to their tank, so it is easy to overfeed your guppies. Take care to only add as much food as they will eat over a two or three minute period.

Adult Guppies

It is generally agreed that after 8 weeks, guppies are considered adult fish. By this stage in their lives, the guppies will be showing their true, full colors. It will be clear which fish are males and which are females.

By 8 weeks of age, it is normal that any female guppy being kept in the company of male guppies will be pregnant. For her first few broods, a young female guppy may only give birth to a small number of babies. Professional breeders separate out their females early on in their lives so they can grow the females into big, strong fish before introducing them to a male. That way the females produce large batches of babies, sometimes hundreds at a time.

By this stage in their lives, adult guppies should be around 1.5″ to 2.5″ (3.8 to 6.0cm) long. The females may well be larger still. Guppies don’t tend to grow much more after about 8 weeks.

Adult guppies need a good quality, varied diet in adulthood, especially if the females are actively breeding. I try and feed my own guppies a good mix of live or frozen food as well as flakes and pellets.

Guppies will generally live for between 3 and 5 years depending on a number of factors including water temperature. Female guppies often continue to produce babies until around 3 years of age.

In Conclusion

Guppies lead a fascinating life. They go from birth to adulthood in around 8 weeks, after which they start working on creating the next generation.

I have been fascinated by guppies since I first started keeping fish, and breeding and selling guppies have funded much of my fish-keeping hobby. These are truly amazing fish that seem to captivate both those who are new to keeping tropical fish and those that have been in the hobby their entire lives.

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