Male vs. Female Guppies – Differences + Identification

The male and female guppies have very different physical and behavioral differences. The differences are in color, shape, and size. However, it is impossible to tell the difference shortly after birth or in the first and second weeks of their life. The best time to do so is after a period of one month.

The most accurate difference between the female and male guppies is the gravid spot on the females because males do not have it. Female guppies are rounded, longer, and plump, while males are shorter and more colorful. Additionally, adult male guppies chase females around to mate.

Male guppiesFemale guppies
They grow 1.5 to 3.5 cm long.Grow from 3cm to 6 cm long.
Their anal fin is long and pointed.Their anal in is shorter and more rounded/fan-shaped.
Male guppies have streamlined, lean bodies.Females are more plump, rounded, and bigger.
Males are more colorful and outstanding.Female guppies are less colorful.
Male guppies are authoritative towards females.Female guppies are less aggressive and shy in general.
Difference between male and female guppies

Male and female guppies will have differences in the shape and size of their body, fins, and behavior. The female guppy will grow faster and bigger as it can grow twice the size of the male guppy, while the male guppy will be more colorful with beautiful patterns.


Male vs female guppies
Male vs. female guppies

To tell the difference between male and female guppies, look at the following;

1. Shape

The male guppy has an entirely different shape from the female. The male is usually very slender with a long body, while the female is rounder and bigger. 

2. Size

The female guppy grows very big as it can double the size of a male guppy. A female guppy can grow as big as six centimeters (2 ⅛ inches), while the male can only grow to three centimeters (1 ⅛ inch). When using this method to differentiate between female and male guppies, it is best to use guppies of the same age or mature guppies.

3. Color

Male guppies are loved because they are the most colorful compared to females. They usually have bright and colorful patterns, especially on their tail fin. The males have their bodies and tails covered in colors such as orange, blue, violet, green, black, and white stripes and spots. 

During breeding, the male will use these colors to attract and seduce the female. Some aquarists claim that the most colorful male guppy can mate with more females than the less colorful.

The female guppies are usually pale grey or silver. However, some breeds of guppies have very colorful females too. But if you compare them with males of the same breed, you will still notice that they are more colorful. When using the color method to distinguish between males and females, you should use guppies of the same breed.

4. The gravid spot

The gravid spot is the most accurate distinction between male and female guppies. It is located on the lower side of the female guppy’s body near the tail.  The gravid spot will get darker when the guppy is pregnant and even darker and bigger when she approaches her delivery day. After giving birth, the gravid spot will get lighter than before the pregnancy. Male guppies do not have a gravid spot.

5. The shape of the dorsal fin

The dorsal fin helps the guppies’ instability, and it is located on the top of the guppy and runs along the back.  Male guppies have a long dorsal fin while females’ is shorter.

6. The size and shape of the tail fin (Caudal)

The tail fin helps propel the guppy through the water and can be used to sex guppies. The male guppy has a long broad tail fin that is usually colorful with beautiful patterns. On the other hand, the female guppies will have a shorter tail fin with less decor. 

7. The anal fin

The anal fin is located under the fish before the caudal fin. The male guppy’s anal fin is long and narrow and has a pointed end. The male guppy uses his anal fin to fertilize the female by inserting it into her anal fin. The anal fin is shorter on the female and has a triangular shape. It is next to her gravid spot.

8. Growth rate

Guppies grow relatively fast, but females grow faster and mature earlier than males. However, the growth rate is also determined by how much food you feed them.

Guppy male and female ratio

Keeping male and female guppies in the same tank can be challenging if you keep them as a hobby and not for sale because they will reproduce a lot. Female guppies can get pregnant from when they are two months old, and they will get pregnant several times a year.

One female guppy can give birth to as many as 60 fries at a time, meaning that without controlling their breeding, you will have so many fries at the end of the year. 

Too many males in the tank will also result in aggression as they will fight to show dominance and mate with females. They will also harass the females all the time to mate with them, even when females are pregnant. Keeping only one male in a tank with three females is recommended to minimize aggression. The number of females can be increased if the tank is big enough.

Importance of telling the difference between guppies

Guppies reproduce by giving birth after a male guppy fertilizes the female through the anal fin. The reproduction rate of guppies is very high because they can give birth to many fries at a time and carry several pregnancies in a year.

For a person rearing guppies in a small tank or as a hobby and not for sale, the many fries can be overwhelming because they will add to the food budget, and you will require a bigger tank. Due to the above concerns, some aquarists prefer to keep guppies of the same gender.


Like telling the difference between male and female platys, separating guppies is hard in the early stage of their lives. However, you will notice their shape, size, and color differences as they age. The male guppy is very colorful and has a beautiful tail compared to the female, and although some breeds have colorful females, too, they still cannot be compared with the male.

Female guppies grow to large sizes, sometimes twice the size of males. The most accurate difference between male and female guppies is the gravid spot on females.

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