Guppies are peaceful, and they rarely attack other aquarium pets. However, when feeding them with your bare hands, you’ll notice that they bite your fingers or hands. Similarly, guppies bite each other’s tails and fins while playing, competing for food or females.

Although docile, guppies may defend themselves or attack by nipping. Sometimes it’s hard to tell if they are playing or having a serious issue. Fighting signs include constant chasing, guppies staying at the top of the tank, hiding, broken fins, or dead fish.

Guppies nipping

Why are my guppies nipping?

Guppies have various behaviors relating to eating, mating, and social interaction. Knowing why guppies bite each other will help you differentiate between harmful and harmless behaviors. Reasons why guppies keep nipping include the following:


Different animals will display affection in different ways. Guppies’ playtime is characterized by swimming frantically around the tank, hiding, and nipping at each other. The type of nipping is harmless and cannot inflict injury unless by accident.

Guppies playing shows they are healthy and enjoying their environment.


There will be competition when you have too many male guppies in the tank and few females. Male guppies are used to dancing off to entice the female to mate, but when the males are many, they will have to show dominance.

One male will often bite others to inflict fear until respected. Keeping one male per three female guppies should help stop this behavior.

The competition will also occur when you put insufficient food in the tank. Alpha males and strong guppies will scare away small and weak guppies to have all the food to themselves. If the trend continues, the smaller and weaker guppies will starve.


Although most guppies are peaceful, there will always be that bully that loves nipping others. The alpha male will always bully other guppies into having the females. A pregnant guppy that is very aggressive will also bite the males to keep them away.

How to stop guppies from nipping

Nipping guppies are dangerous and should be stopped because they can injure others. Below are ways you can use to stop nipping guppies.

1. Keep more females than males

Keeping more females than males will reduce the harassment of females by males in an attempt to mate. The conflict between males looking for dominance will also be reduced. You should keep a ratio of three female guppies in a tank with one male guppy.

2. Put up hiding places

It’s worth noting that guppies stay at the top of tanks or hide in plants and caves when bullied. Bullied guppies are unhealthy, and you should intervene to help them. Provide hiding places such as ornaments, driftwood, and caves.

3. Provide sufficient food

To stop bullying and competition during mealtime, feed them enough food. You can feed the guppies twice a day. A healthy diet helps a guppy regrow its tail or fins when damaged. Generally, proper feeding improves the fish’s immune system for faster healing from infections and injuries.

4. Increase the size of the tank

Keeping guppies in a small tank will stress them, making them aggressive. They will not have enough space to swim, play or hide. Therefore, use a recommended guppy tank size for your fish.

Experts recommend keeping 4 guppies in a t10-gallon tank. Each guppy will require 2.5 gallons of water space. If your tank is small, you should get a bigger tank or give away some guppies to friends and family.

5. Move the bully to a separate tank

If the guppy bullying others does not stop even after taking the above measures, the solution will be to move it to a separate tank. You can keep it in a separate tank and then return it to the parent tank after some time.

If the aggression does not stop, it is time to move it to a separate tank permanently.

Note that the mating behavior of guppies can sometimes be mistaken for bullying. Before you conclude that the guppies are fighting, observe closely to eliminate the possibility of mating.

How to tell if guppies are fighting or mating

It is usually hard to tell if guppies are fighting or mating because they will portray similar behaviors on both occasions. However, you can look out for the following.

Broken fins

When guppies fight, they will nip each other’s fin and tail to inflict pain, resulting in an injury. They do not cause any damage during playing or mating unless by accident.  However, you should ensure the damage is not caused by the fin rot disease.

Fish hiding

Happy fish will swim around the tank. Therefore, if you spot guppies hiding behind the plants or ornament, it indicates bullying within the tank. Observe closely and remove the bully from the tank.

Dead guppy

You should check the water parameters when you have a dead guppy in your tank. Check the pH, temperature, ammonia, and nitrate levels because they are the major fish killers. If the parameters are okay, check the dead fish for signs of bullying, like broken fins and tails.


Like in humans, bullying is traumatic, and it takes a while to overcome it. Moving the aggressor from the tank is the best way to help a bullied guppy.  If the guppy sustains minor injuries, it will heal on its own. However, you should consult a veterinarian for severe injuries.

To stop guppies from nipping, you should provide hiding places, give sufficient food, increase the tank size, and keep more females than males.


  1. The University of Nebraska: Evidence for Mate Choice by Male Guppies
  2. The University of Chicago Press Journal: Life‐History Evolution in Guppies

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