How Big Do Guppies Get?

Guppies are one of the most popular aquarium fish, thanks to their vibrant colors and ease of care. But when you bring home a new guppy, you may be wondering how large it can grow to be. 

In this blog post, we’ll discuss how big guppies get and what factors influence their size. 

Guppy Size Range 

Guppies are a popular freshwater fish native to South America, renowned for their variety of intricate color patterns, and the ease of breeding them. 

Although guppies generally range from one inch to two inches in length, some varieties may reach outside this size range. 

Endler’s livebearers, for example, are much tinier than the average guppy, only growing as long as half an inch. 

On the other hand, show guppies bred for their aesthetics can grow up to three inches in length. 

These small sizes make them perfect for smaller tanks, as even the biggest guppies won’t outgrow their home too quickly. 

Additionally, their small size also means that they produce less waste than larger species of fish. This is great news if you don’t want to clean your tank often! 

No matter what size or variety of guppy you choose, these beautiful little fish make great additions to any aquarium!

The Standard Guppy 

The standard guppy is the most common type of guppy and has a size range between 1–2 inches in length. 

This type of guppy is typically known for its bright colors and wide tail fins. Because these guppies are smaller than other types, they can be housed in tanks as small as 5 gallons. 

While it is possible to breed standard guppies, it is not recommended, as this can lead to overcrowding in a tank, which can cause stress to your fish. 

The Endler Guppy 

The Endler guppy is a smaller version of the regular guppy and only grows to around 1 inch in length. 

Unlike standard guppies, endlers generally come in solid colors such as black or red, and have shorter fins than their larger counterparts. 

Endlers also require less maintenance since they need fewer resources to thrive than other types of guppies. Because they are so small, Endler guppies can even survive in bowls as small as 2 gallons! 

The Fancy Tail Guppy 

The fancy tail guppy is the largest type of guppy available, growing up to 3 inches long! These larger-sized fish are usually brightly colored and have beautiful tails. 

Fancy tail guppies require more space than other types because they can grow much larger than their smaller counterparts,

Therefore, it’s best to house them in tanks no smaller than 10 gallons if you plan on keeping them for any extended period of time. 

Additionally, due to their large size, fancy tail guppies should not be kept with smaller varieties, like the endler or standard varieties—since the smaller fish could easily become lunch for the big fish!  

Factors That Affect Guppy Growth 


Taking care of guppies requires more than just fresh water and a suitable tank size – the temperature can play a huge role in their growth and development. 

To ensure your guppies are healthy and growing, the water temperature should ideally be between 77 and 86 degrees Fahrenheit. 

If the water is too cold, it can slow down their metabolism, preventing them from gaining weight or reaching their full size. 

All aquarium owners should invest in an aquarium thermometer to keep an eye on the temperature in the tank.

Checking the temperature periodically will help make sure that your guppies are getting the environment they need to grow strong and healthy!

pH Level

Water is essential for fish to stay healthy and grow, but not just any water will do. The pH level of the water has a big impact on guppy growth.

Guppies prefer water with a pH level between 7.0 and 8.5. If the pH goes outside of this range, it can cause stress for the fish, which can stunt their growth. 

To ensure your guppies are growing properly, it is important to invest in a good pH test kit, so you can always check the levels in your tank and make adjustments if needed. 

With ideal water conditions and plenty of nutritious food available, your guppies should be able to reach full size within a few months!

Ammonia Levels

Ammonia is an invisible yet deadly threat to our aquariums. If the levels in your water become too high, it can cause heavy stress to your guppies and inhibit their growth. 

Stressful conditions often cause fish to expend energy just trying to stay alive instead of actively participating in the basic biological functions they would otherwise use to grow. 

So while you might not be able to see ammonia in the water, you can recognize its effect indirectly through slower guppy growth.

This is coupled with other signs, such as a lack of energy and labored breathing. To ensure that your fish stay healthy, measure the ammonia levels regularly and take action if too much is detected.

Nitrate Levels

The presence of nitrates in the water can be particularly detrimental to guppies since they are naturally sensitive to such toxins, and thus, more vulnerable to their effects. 

In particular, high levels of nitrates can cause significant stress for fish, making it more difficult for them to grow quickly, and resulting in stunted growth. 

To prevent this, aquarium owners need to ensure their water is free from any dangerous levels of nitrates by employing proper maintenance.

Oxygen Levels

One of the most pertinent environmental factors that can influence guppy growth is the amount of oxygen available in the water. 

All fish require oxygen in order to survive, and if their aquatic environment does not offer enough of it, their growth rate can be drastically reduced. 

This stress imparted by inadequate oxygen levels may even result in a decrease in energy, resulting in poor feeding and compromised immunity that affects the animal’s overall health. 

The best way to ensure that your guppies have access to optimal amounts of oxygen is to regularly check water parameters, or use an aerator device if needed.

Food Quality

High-quality food is essential for providing guppies with the proper balance of protein and nutrients that they need to grow. 

When guppies receive a diet that is low in nutrition or lacks key vitamins and minerals, they can experience stunted growth, which could impact the overall health of the fish. 

Fortunately, there are now plenty of specialized food options available that can provide guppies with all the nutrition they need to grow at their normal rate. 

With so many fish foods to choose from, it’s important to pick one that contains a high-quality mix of proteins and minerals, such as wheat germ-based flake food or frozen shrimp.

Doing research into the best type of fish food appropriate for your guppy’s needs will help ensure your guppies maintain optimal growth rates throughout their lifetime.

The Growth Cycle of Guppies 

Freshly-hatched guppy fry are truly amazing to observe, as you can watch them grow from a tiny speck of a baby fish into an adult in the span of just a few weeks. 

At birth, they measure no more than a fraction of an inch, yet within three weeks, they’ll have adapted to their environment and grown up to three times that size. 

As they become accustomed to the tank conditions, their diet, and other inhabitants, they develop a higher level of efficiency in food processing, and their rate of growth increases rapidly. 

Once fully mature, their growth rate slows significantly until it has all but stopped at around two months post-birth.

This makes for a unique development cycle that is guaranteed to captivate any aquarium hobbyist!

Guppy Lifespan 

Adult guppies have a relatively short lifespan, usually ranging from one to three years. Many hobbyists and fish enthusiasts have reported keeping much older guppies than expected!

The length of their life is highly dependent on the care they receive—such as if the water parameters stay consistently within healthy levels, and the fish are fed high-quality food.

It’s important to take good care of our pets in order for them to lead not only long lives, but also happy and healthy ones!    

The Benefits Of Owning Guppies 

For anyone looking for a low-maintenance pet that won’t take up too much space or require too much care, guppies are a great choice! 

Their small size means that you don’t have to worry about them getting too big for their tank or producing too much waste –- all while still providing the joy of owning a pet fish! 

Plus, because there are so many varieties available—from fancy tail types to vibrant colors—you can find the perfect type of guppy for your home aquarium.  


All in all, it’s clear why so many people choose guppies as their pet fish! They stay relatively small in comparison to other species, and require minimal care and maintenance on your part.

They come in tons of different varieties, so you can find one that matches your style preferences perfectly. 

So if you’re thinking about adding some color to your life with a new pet fish—guppies might be the perfect choice for you!

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