Of all the livebearer fish species, it’s the easiest to tell male and female guppies apart. You can easily tell the male from the female guppies by just looking at their color. Male guppies are more colorful and vibrant with showy tails, while female guppies are drab and larger in size. Below you will find four easy ways to tell male and female guppies apart.
Four Ways to Tell Male and Female Guppies Apart
1. Male Guppies are More Colorful than Female Guppies
The main way to tell male and female guppies apart is to look at the color of your guppy. The male guppy is colorful, with vibrant patterns and colors on its body and tail.
The female guppy, on the other hand, is more drab looking. The bodies of female guppies are usually plain gray. The tails of female guppies have a little color on them, but it’s not showy and vibrant like the tails of male guppies.
2. Male Guppies Have Long Anal Fins (Gonopodiums)
Another way to tell male and female guppies apart is to look for the gonopodium. Like other male freshwater livebearers, male guppies have a modified anal fin called a gonopodium (anal fins are the fins at the bottom of the fish). While female guppies don’t have a gonopodium.
Gonopodiums look like long, pointy anal fins. Look at your guppies, male guppies will have a long, pointy gonopodium. While female guppies will have anal fins that are rounded.
3. Female Guppies are Bigger and Fatter
Another way to tell male and female guppies apart is to look at the size of the guppies. Female guppies are fatter, rounder, and bigger than male guppies.
Take a closer look at your guppies. The bigger and fatter guppy is probably the female. Verify the sex of your female guppy, check that she does not have a gonopodium, and look at her body color (should be drab).
4. Female Guppy Have a Black Spot on her Belly
Look for a black spot on the belly to distinguish between male and female guppies. A female guppy will have a black spot on her belly. This black spot is called the gravid spot.
Look closely at your guppies. You will see a black, gravid spot on the belly of your female guppies. Verify that she is indeed a female guppy by also checking to see that her anal fin is round (no gonopodium) and that she is not colorful.
On the other hand, male guppies will not have any signs of a black spot on their belly. The belly of male guppies will also look thin. You can easily verify that your male guppies are truly male by looking at their color; they should be colorful with long and pointy anal fins (gonopodium).
If your female guppy is pregnant, the black gravid spot on her belly will look darker and more pronounced. Some say they are the baby’s eyes!
Is the Black Spot on the Belly (Gravid Spot) Only Seen in Female Guppies That Are Pregnant?
Even if your female guppy is not pregnant, you can still see the black spot on her belly. The gravid spot may not be as dark and prominent on the non-pregnant female guppy, but you will still be able to see it.
How to Tell Young Male and Female Guppies Apart?
When they are young, all guppies look like female guppies. Young guppies have grey bodies with little coloring. As your guppy matures, you will start to see the colors come out. Even before they start developing their colors, you can still tell young guppies apart by looking for the gonopodium.
Look closely at your young guppies. Look for the tell-tale signs of gonopodiums on male juvenile guppies. They look like pointy anal fins. It’s really difficult to see because they swim fast and the gonopodium is almost transparent.
Keep checking on your young guppy. Eventually, the gonopodium can be seen with your bare eyes and you will be able to tell the young female guppy apart from the young male guppy.
From my personal experience, I have seen the gonopodiums of young guppies when they are 4 weeks old. Before that, it was really difficult to see. I probably have to have a magnifying glass to really see the gonopodiums of the baby guppies!
Quiz: Can You Tell the Male and Female Guppies Apart?
After reading this article, I hope you learned to tell the difference between male and female guppies. Take the quiz below, find out if you can distinguish between male and female guppies.