Why Do Guppies Chase Each Other? (Prominent Reasons)

Why Do Guppies Chase Each Other? (Prominent Reasons)

Image of guppies chasing each other

Guppies chase each other due to food scarcity, overcrowding, absence of a mate, or while playing. They also do it to show dominance, safeguard their territory, or form a hierarchy. Male guppies chase females for mating, while pregnant female guppies chase others when hungry or to exert dominance.

Let’s now discuss all the possible reasons why guppies chase each other.

Is It Normal For Guppies To Chase Each Other?

Chasing is common among guppies.

You will notice your male guppies chasing the female guppies during the breeding season.

However, sometimes guppies tend to chase each other when they are in a playful mood.

Chasing is not alarming as long as there are no signs of aggression.

But you should intervene if you find your guppies getting aggressive. Otherwise, you may end up with an injured fish.

Reasons Why Guppies Chase Each Other

Given below are some of the prominent reasons why guppies chase each other.

Mating ritual.

Mating is the primary reason for guppies to chase each other. Male guppies chase females around the tank during the mating ritual.

The male guppy will swim up and down in front of the female, chasing her until she is receptive to mating.

Mating can take anywhere from 10 minutes to several hours until the female guppy agrees to mate.

The reason male guppies chase females is that they want to find them again after copulation.

If he doesn’t catch her right away, then he may not get another chance.

Chasing for mating purposes is harmless as it’s natural during the breeding season.


Guppies also show dominance by chasing others out of their territory.

They use this as an intimidation tactic so that no one else tries to invade their space.

If you have some timid guppies along with a dominant male guppy, it will chase the timid guppies to show his power.

Such chasing is not aggression, but it’s to display dominance.

Male guppies usually show such dominance to form a hierarchy within the group.

Dominant guppies usually keep themselves at the top of the hierarchy.

They use this position to take advantage of the weaker members of the community.

Food scarcity.

Food scarcity is another primary reason for guppies to chase each other.

If guppies are hungry, they will start fighting for food and chasing each other.

Hunger can lead to aggression between two guppies as they will compete for the limited amount of food available in the tank.

The timid guppies are the worst affected as the dominant guppies will scare and chase them away from the food source.

Lack of space.

Guppies need ample space to swim freely in the tank.

If you have a small tank, your guppies will be forced into tight spaces without much room to move around.

In these situations, guppies tend to become aggressive towards each other, resulting in chasing.

In nature, fish species often engage in behaviors such as chasing or fighting among themselves.

These natural behaviors help maintain social order within groups.

However, if you keep your aquarium too small, you might end up seeing similar behavior in your guppies.

The number of guppies in the tank determines how much chasing guppies resort to.

A large group of fish will cause more fighting than a small group as it restricts their free movement.

It may also lead to stress which will further trigger aggressive behavior among guppies.

They will start to chase and even harm submissive tank mates.

Incorrect male to female ratio.

Guppies are prolific breeders. They have a strong urge to mate during the breeding season.

If you have a tank with male guppies outnumbering the females, the chances are high that the males will try to mate with any female guppy that comes near them.

This leads to constant chasing and fighting among the males.

The males compete for access to the females.

If the competition becomes intense, the males even resort to physical attacks on each other.


Every individual needs a private space to live comfortably. Similarly, guppies also need their territory to feel safe.

Usually, there’s not enough space in the home aquarium compared to the natural environment.

Hence, when guppies live together in close proximity in an aquarium, territorialism sets in.

Guppies try to establish territories in the limited space available in the tank.

Guppies have their area of influence. They guard their territory against intruders.

Any intruder trying to enter their territory gets chased away.

Establishing a territory also ensures that guppies have a sheltered area to feel secure.

Unfavorable living conditions.

Guppies need favorable living conditions to thrive. If the conditions are not conducive, it can lead to stress.

Guppies can respond negatively if they are in discomfort. It can lead to chasing under stressful conditions.

Poor water quality, overcrowding, scarcity of food, bullying, water parameters outside the optimal range, illness, and lack of mates can cause stress among guppies leading to chasing and aggressive behavior.


Guppies are social as well as playful creatures. They chase each other while playing as it helps them bond better with one another.

If you find your guppies chasing one another without any signs of aggression, then they are just having fun.

You need not panic as playing is a good exercise for guppies.

Why Do Female Guppies Chase Each Other?

Female guppies are usually docile. Seldom do they fight or chase other female guppies.

However, if there is a dominant female guppy, then she may bully and chase weaker ones.

The reason why these bullies behave aggressively towards weaker ones is that they don’t like sharing resources.

The most common way through which dominant guppies exert control over subordinates is by intimidating them into submission.

Apart from exerting dominance, the other time female guppies chase each other is when they are pregnant.

This is because pregnant guppies need more nutritional food during pregnancy.

Hence, they may chase others during feeding time to get adequate food.

Why Do Male Guppies Chase Each Other?

Male guppies chase each other to establish dominance.

If you have a male-only guppy aquarium, the dominant guppy will chase the other guppies to scare them away and form a hierarchy.

Besides, guppies tend to chase anyone that enters their territory.

The reason behind this is to protect their territory from intrusion by others.

A male guppy chases its rivals by:

  1. Swimming toward the enemy.
  2. Nipping the body or fins of the rival.

The first method is used more often than the second. However, a male guppy uses both these techniques simultaneously.

Besides, male guppies chase each other if there are no females around to mate. It happens due to frustration.

Guppies are wired to mate and can get stressed in the absence of females, leading to the chasing behavior.

Why Do Male Guppies Chase Pregnant Female Guppies?

Male guppies chase pregnant female guppies because they want to mate with her.

Pregnant female guppies are usually found alone in the aquarium.

Hence, male guppies try to impress her by showing off their strength and prowess.

A pregnant female guppy usually doesn’t mate until she has delivered all her fry.

Hence, male guppies relentlessly chase the pregnant female guppy to drop her fry so that they can mate again.

Constant chasing can be stressful to pregnant female guppies. It may even lead to miscarriage.

So, you need to keep an eye on your fish tank during the pregnancy period.

The other way is to separate the pregnant female guppy and keep her in a breeder box to avoid constant harassment.

Why Do Male Guppies Chase Female Molly?

Male guppies chase female mollies for mating purposes.

If you have a community tank holding guppies and mollies, chances are, the male guppies will look upon the female mollies as prospective mates.

This mainly happens when there are fewer female guppies around to mate.

Male guppies mate with female mollies as both these species are similar in size, color, and shape.

Other than mating, male guppies may chase female mollies if they intrude in their territory.

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