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How Big Do Guppies Get – Explanation

Do you want to know the size of your guppy fish can grow? As there are many different types of guppies, it all boils down to which species you plan to get or own. So, how big do guppies grow?

How Big Do Guppies Get?
How Big Do Guppies Get?

Baby Guppies & Their Growth Rates

Baby guppies mature within 2 to 3 months. At birth, they are between 1/4 and 3/4 inches (1.2 to 2 cm) in length. Within a month, you can expect them to grow to an inch under optimal conditions.

At this stage, they lack color and are mostly thin. However, within 30 or 40 days, they start to develop color (which you can notice daily) and are able to reproduce. At 2 months or a little more, you fry will have fully matured into adult guppies.

To guarantee that your baby guppies grow at a healthy rate, feed them a variety of quality foods several times per day, and change the aquarium water on a weekly basis.

Things To Consider

The size of your guppy will also be influenced by what you feed your guppy and how often you feed your guppy. Not only does the food source influence how big your guppies grow, but it also influences your guppies’ lifespan.

This is why guppies in captivity tend to grow bigger than guppies in the wild. The fish food, insect larvae, and the different vegetables that you feed your guppy help this.

Also, due to selective breeding,  larger body size and are much more extravagantly decorated varieties occur in captivity when compared to their wild counterparts.

How big do guppies grow?
How big do guppies grow?


In order for your guppies to grow to their full potential, they need a large aquarium. Small spaces and overcrowding will stress your guppies and hinder their growth. A 10-gallon tank should do the trick for 3 to 5 guppies. Increase the size of the tank accordingly as you add more fish.

The amount of water in the fish tank will also influence the growth of your guppies. Things like the temperature level, oxygen level, and the cleanliness of your tank play a role in your fish’s development.

A heater, a filter system, and regular water changes will aid in providing a good environment for your guppies to grow. As a rule of thumb, 1 gallon of water per 1 inch of fish should suffice for small fish like guppies.

Crowded Tank

Too many fish in a tank leads to many issues including but not limited to health problems due to the lack of oxygen, high toxins levels, and the stress of being in a crowded tank.

You can prevent overcrowding by keeping a male to female ratio of 1:3 and control the population in your tank by limiting breeding. A good way is to try to only male guppy fish.


Your guppies can grow to a size anywhere between 1.2 to 3.5 inches. However, factors such as genetic, water parameters, tank size, and diet all play an important role in the growth rate and size.

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