Guppy Fish Male to Female Ratio in a Tank

If you’re planning to get an aquarium and keep pet fishes, Guppies are among the few fish species you can begin with. And one of the easy to maintain, yet beautiful and elegant-looking fish to keep is Guppy.

Guppies are tiny and beautiful and they need very little care. However, it doesn’t mean that you can keep them as you wish. Guppies are livebearers and they mature pretty fast. And their ability to reproduce is also pretty high.

But, it is crucial to understand the importance of male to female ratio. And this article is a perfect guide for you.

Guppy Male to Female Ratio in tank

Why is it Important to Maintain a Proper Ratio?

The usual ratio to keep guppies is 1:3, i.e. for every one male guppy, there should be three female guppies in a tank. This is the perfect ratio to keep the guppies if you’re planning to keep them as pets.

Having too many males and fewer females is not a good idea. Male guppies would go around chasing females in attempt to please them.

And if there are more males than females, they’ll still chase them around. The chasing eventually becomes stressful for the female guppies to handle. Their immune system starts deteriorating if it continues. And it leads to contracting various diseases, possibly death.

So, it’s crucial to maintain the 1:3 ratio as much as possible.

Can you keep only male guppies in a tank?

Guppies mature pretty quick and can reproduce rapidly. And it can lead to over crowding of the tank and pollution. We now know why we shouldn’t keep more males and less female in a tank.

But you could be wondering if it’s okay to keep an all-male guppy tank.

I have to admit, it is a possibility, however, its not a proper solution. Yes, they are more vibrant than female guppies. They’re also more active and tend to run around putting up a show. Yet, you don’t want to risk keeping all-male guppies in a tank.

Guppies aren’t very aggressive in nature. But one thing they love to do is put on a show for female’s attention. They sort of put on a healthy competition and when you just keep male guppies together, they might try to kill each other. But there is high risk that they’d fight pretty often.

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If the group is smaller, say of 2-3 guppies, it’s riskier. In such cases usually one guppy tends to act more superior while other have to follow him. The dominant guppy then bullies the inferior ones and the situation becomes hard to handle. Therefore, if you want an all-male guppy tank, have a large group instead of up to 4-5 guppies.

But as mentioned earlier, it’s better to keep male and female guppies together maintaining the 1:3 ratio. It’ll keep a healthy balance between the fishes and the environment more peaceful.

How to Identify the Gender of your Guppy Fish?

You can tell male and female guppies apart a bit easier as they start to mature. But during the fry-phase, it’s a bit of a pickle to tell them apart. And it’s important to tell them apart so you wouldn’t overcrowd the tank with the same gender.

Top: Male; Below: Female

Thankfully, the best thing about this fish is that they mature quicker. And within a week you can look for ways to tell them apart. But If you take more time, it’ll be too late.

So, here is how to identify the gender of your guppy fish.


It’s a known fact that male guppies are more colorful and vibrant than their female counterparts. And easily, the male guppies grow up to have more eye-catching colors all over their bodies.

The vibrant colors and beautiful stripes and patches set the male guppies apart from the female guppies. And it also help them get more attention from both humans and female guppies.

Body Shape

While figuring out a more vibrant and colorful guppy is an obvious way to differentiate the gender, it’s not always helpful. So there are other ways to determine if you have a male or a female guppy.

And another great way to differentiate their gender is by focusing on their body shape.

Male guppies have a longer and more slender bodies compared to the curvier, more rounder female body. Female guppies are larger than males, nearly double in size.

The best time to figure it out is, however, while they’re swimming. As their bodies are in proper display and you can take a good look with a magnifying glass in hand.

The Gravid Spot

One of the best ways to figure out if your guppy is a male or female is by spotting the gravid spot. This method is fairly easy because the gravid spot is found only in female guppies. It is a dark spot that you can find near the tail of the female guppy.

When female guppies get pregnant, the spot tends to grow bigger and darker. It is because the developing fry inside the belly presses against the body. But the spot visibly gets lighter after she gives birth.


Another way to differentiate if you have a male guppy or a female guppy is paying attention to its fins.

Fins play an important part in making guppies who they are. And by figuring it out, you’ll know if your guppy whether a male or a female.

Caudal fin, or guppy’s tail fin is located in the tail area. In males, the caudal fins are long, wide and colorful. While the female have a shorter and less wider and colorful caudal fin.

Dorsal fin is located at the top of the guppy which is nearer to it’s head. Female tend to have a shorter and smaller dorsal fin. Whereas, male guppies have, again, big fins that flows in the water and is visually pleasing.

And finally, the anal fin or gonopodium that lies under the guppy fish. It is right before the tail fin and is a little smaller than it.

In male guppies, the anal fin is is long and appears narrow and pointed. But in female guppies, it is more triangular and is much smaller than what males posses.

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