How Long Does It Take For Guppies To Grow To Full Size?

Are you wondering how long does it take guppies to grow to full size?

Guppies fry can take care of themselves from the moment they are born, but you can lend little help to make the growth process faster and easier.

Guppy fries are already fully formed when they are born with an average size of 0.25 inch.  You can help them create an atmosphere that makes the growth process easier for them.

How Long Does It Take For Guppies To Grow To Full Size?

Guppies grow to full size in about six months under suitable conditions.  Guppies attain a maximum size of about 1.5 inches for males and 2.5 inches for females without counting the tail in about six months provided all conditions are made favourable.

Good water parameters, proper feeding, compatible tank mates and suitable tank size are some of the factors that contribute to healthy and fast growth.

Guppies To Grow To Full Size

Are You Looking To Keep Guppies? If yes check out our care guide here

Guppy Fish Growth Stages

Guppies have a simple life cycle and reach full adulthood after just four stages. These fishes require different care in each stage for you to have healthy and colourful guppies. Here are the growth stages of guppies.

1. Guppy Fry

Guppies are livebearers and guppy fry are free-swimming right from the moment they are born. They are initially deformed but straighten up after a few hours before they are strong enough to start feeding.

Guppy fries are small [about 0.25 inch] in length. Their small size is why they are prone to preying by bigger fishes and aquarium owners need to protect them.

Guppy fry will eat the same food as the adult guppy. However, feeding them with live food and baby brine shrimp are more beneficial to them.

The yolk of the hard-boiled egg will also significantly help their growth. Frequent water changes, leaving the light on for 12-16 hours are also important for their growth.

2. Juvenile Guppy

It takes about one month for guppy fry to become juvenile. At this stage, the first thing they develop is distinguishable colours. Their sexes are also distinguishable at this stage.

The females will become visibly larger than the females and their gravid spot becomes obvious. The gonopodium of the male will start forming as well.

Guppies at this stage are about 0.75 inches in length. This stage is one of the most important in the life cycle of guppies therefore it is important to keep all environmental conditions favourable.

They can comfortably feed on blood worms, brine shrimps, beef heart and high-quality flakes at this stage.

3. Young Guppy

Guppies reach the young guppy stage at approximately two months and this stage is significantly marked with gradual sexual maturity. They become sexually active after about two months and it is the perfect stage if you intend to separate male and females.

It is better to separate them because the males are already sexually active while the females are still focusing on growth rather than reproduction.

Feeding guppy at this stage is relatively easy, you just have to lower their fat intake and feed them with more protein and greens. Feeding spirulina and plankton pellets will also help the guppy develop intense colour.

4. Adult Guppy

You can refer to guppies as adults at this stage. Depending on factors and genetics, they can be around 1.5-2.5 inches. Their growth will significantly slow down at this stage and the fins and tails of male guppy will get longer.

You need to feed your guppy with a variety of food predominantly protein with low fat to keep them healthy and colourful. Adult guppies become infertile when they are about 2-2.5 years old, but they can live up to 2-5 years.


Knowing the growth stages of guppies is very important in knowing how to feed and take care of them. You need to make all factors and feeding favourable for them to remain healthy and colourful.


Hello, I'm Jason. I'm the guy behind I volunteer at my local fish shop and I created this site to offer tips and advice on the fish I care for.

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