Male Vs Female Guppy: Top 7 Traits That Tell Them Apart

male vs female guppy
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Last Updated: September 4, 2023 by Flora Gibbins

Are you interested in raising guppy fry? These fish are truly breathtaking and a joy to look at their brightly colored bodies. Moreover, they are not high-maintenance.


Is it possible to differentiate between male and female guppies? Yes, you can.

This article outlines seven ways to do so. With these factors at hand, you will be distinguishing male guppies from female guppies in no time.

Read on.

Main Differences Between Male and Female Guppies

male and female guppy image

The main differences between male and female guppies are:

  • Male guppies have thin, long bodies, whereas females are bigger and rounder.
  • Male guppies have bright, vibrant colors, whereas females are less colorful.
  • Male guppy fish have pointed anal fins, whereas female guppies have a triangular anal fin.
  • Female guppies have a gravid spot, whereas males do not.
  • Male guppies have long dorsal fins, whereas female guppy fish have a short dorsal fin.

Read on for more information.

7 Ways To Differentiate Male and Female Guppies

1. Check the Guppy’s Body Shape and Size

Adult male and female guppies have different body shapes.

male guppy with plants background

Male guppies have thin but long bodies, while female fancy guppies are generally rounder and bigger.

This is particularly evident when female guppies get pregnant and have bigger, lumpy-looking bodies.

Moreover, females grow to reach 2-1/8 inches long. Meanwhile, males only get to 1-1/8 inches. This means that anytime you see a slender guppy, it is likely a male. On the other hand, if the guppy is a lot rounder, it is a female.

2. Look at the Guppy’s Body Color

You might be surprised by this, but male guppies have more bright, colorful bodies than females. Experts explain their bright coloring as an adaptation to help them draw the attention of a female mate.

male guppy fish snakeskin

Male guppies have colorful bodies with different patterns, while the females have silver or pale gray bodies.

Does that mean there are no colorful female guppies? No. However, even when these females have colorful bodies, they are no match for the magnificent males.

So, the next time you walk to a guppy tank and need a female guppy, it might be one of those less colorful guppies.

However,note that the color difference is not as evident with wild guppies as is with captive-bred guppies. With this in mind, let us examine more factors.

3. Check the Size of the Guppy’s Anal Fin

The anal fin is a sure way to identify male and female guppy. The anal fin is that small fin located on the bottom side and close to the tail fin. It sits between the paired fins and ventral fins.

male and female guppies in aquarium

Males have long, narrow, and slightly pointed anal fins.

The anal fin loses the triangular shape to make room for the gonopodium. The gonopodium is the male’s reproductive organ that may look long and pointed or like a rolled tube. Male guppies use this ‘special’ anal fin to insert sperm into the females. Unlike males, female guppies have a triangular anal fin. Their anal fin does not undergo any changes.

4. Examine the Guppy’s Dorsal Fin

You can also use the guppy’s dorsal fin to determine the sex of a guppy. The dorsal fin is that fin on the top part of the fish’s head.

The males have longer dorsal fins, while female fancy guppies have shorter dorsal fins.
guppies at the bottom aquarium with pebbles

The difference is evident when the two guppies move in the water. Male guppies have flowing dorsal fins compared to their female counterparts. The females’ dorsal fins do not trail or stream when they swim.

5. Check the Guppy’s Tail Fin

The shape and size of the tail fin (caudal fin) is another way to identify male and female fancy guppies.

Male guppy fish have long caudal fins, while females have shorter caudal fins.
beautiful guppy in aquarium

The male guppy’s tail fins are also wide and brightly colored with intricate and elaborate patterns. However, the females have narrower caudal fins that lack fancy patterns and bright colors.

6. Look for A Gravid Spot

The gravid spot is the reproductive organ in a female’s body. Therefore, the presence of a gravid spot confirms the guppy is a female. But where is this dark spot located?

Well, this dark area sits close to the anal fin. The pointed, anal fin helps identify a male while the gravid spot identifies a female.

When a female guppy fish gets pregnant, the gravid spot gets darker and expands as the due date approaches. The darker the spot, the sooner the female is about to give birth to her live fry.

Once the female guppy gives birth, the gravid spot becomes lighter. However, the cycle repeats when she broods again.

The gravid spot is a certain way to determine the sex since female fancy guppies are almost always pregnant. Female guppies can store a male guppy’s sperm for up to six months. This means that the female guppy fish will get pregnant every month without having to mate.

7. Growth Rate

Some guppy fry grows faster than others, and this is at times attributed to their sex. Female guppies are perceived to grow faster than their male counterparts.

However, it is arguable that guppy fry that receives nourishment will grow fast, whether male or female. So, when determining between a male and female guppy, do not rule the sex based on this single factor.

Are There Differences Between Wild Guppies and Captive-Bred Guppies?

Yes. There are notable differences between wild and captive-bred guppies. For starters, a wild male guppy does not display vibrant colors as a captive-bred. Breeders have highlighted the guppy’s colors through selective breeding, hence the distinction.

In addition, captive-bred males come with different tail shapes and patterns not found in the wild. It is extremely rare to find a wild betta with a lyre tail, delta tail, or sword tail.

The females, too, have their differences. Wild female guppies have melanophores on their skin that help them camouflage as they hide from predators. They also have gray or brown color tones with no distinct colors, which is different from captive-bred female guppies.

How Many Male Guppies Should You Keep with Females?

You must have a balanced ratio of males and females when keeping this fish species. Doing so will prevent overbreeding and reduce aggressive behavior.

If you did not know, guppies are also called ‘million fish’. Why? They not only breed easily but fast too. If you are not careful, you will be raising a guppy fry every month.

Also, when you put the incorrect ratio of males and females, the males are likely to get aggressive towards the females. Constant aggression can stress and even kill the females.

With this in mind, we recommend housing one male guppy with three females. Alternatively, you can have a separate tank for males and females if you are not looking to breed guppies. Either way, your guppies will lead a comfortable and healthy life.

Fun Fact: Wouldn’t it be nice if you knew that there are different guppy species available in the market? Know them all by reading our post Types Of Guppies: 56 Fish Varieties To Keep You Preoccupied to help you identify your aqua pals.

Do Water Temperatures Influence Whether the Baby Guppies Will Be Male or Female?

Studies are currently underway to determine whether water conditions determine the sex of a guppy. Nevertheless, commercial fish farms have been using thermal manipulation to get the fry gender they want.

Through these breeding programs, the farms have observed that keeping the pregnant females in low temperatures leads to a high number of female fry while warm temperatures increase the number of male fries.

When is the Best Time to Differentiate Male and Female Guppies?

Male and female guppy fry look the same. It is impossible to tell the sex of guppy fry when they are less than four weeks.

But at 4 weeks, the baby guppies reach sexual maturity and undergo developmental changes.Parts like the anal fin and gravida spot have developed to make the distinction.This is why we recommend 4 weeks as the best time to differentiate between male and female guppies.

Frequently Asked Questions

Should I have more male or female guppies?

When keeping guppies, we recommend one male for three female guppies. If you were to have more males than females, they would stress the female from constant attention and aggression.

Can I tell male and female guppy fry apart at one week old?

Sure, but you will require a magnifying glass. Guppies mature from four weeks old. Therefore, you will not observe any differences. However, you can use the magnifying glass to look for the gravid spot. The gravid spot is usually developed this early, and it determines the sex of the guppy fry.

What can I do to see the gravid spot?

Get a flashlight and magnifying glass. Switch off the lights and shine the flashlight behind the female guppy. You will see a dark spot under the guppy’s tail. If the fish is pregnant and about to give birth, you might also see her young live fry moving around.


At this point, you can differentiate male guppies from female guppies. We have established seven ways to do so. The most accurate methods are checking the anal fin, dorsal fin, and gravid spot.

These fish are calm and peaceful whether you get a male or female. Guppies make excellent pets and are easy to care for.

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