Which Piranha Is the Most Aggressive? {Will They Eat Each Other?}

Are you trying to compare different species of piranha to find out which is the most aggressive?

Will aggressive piranhas eat each other?

In this article, we’ll find out which piranhas are the most aggressive.

Which Piranha Is the Most Aggressive?

The most agressive piranha is the Red-Bellied Piranha followed by the Black Piranha (Redeye Piranha) and in third place, we have the Caribe or Black Spot Piranha.

We welcome your opinions and experiences and would love to hear your stories about the piranha you believe is the most aggressive if you don’t agree with our ranking order.

What Is The Most Aggressive Piranha?

Piranhas are mostly found in their natural habitat in and around the Amazon River of South America. Among the variety of species, the red-bellied piranha has become to most popular to keep in captivity among aquarists.

The red-bellied piranha is more carnivorous than most species of piranhas, but they continue to scavenge and forage for edible debris such as fallen fruits and seeds. They seem to have the strongest jaws and sharpest teeth among most piranha species.

Due to their popularity, they are involved in more incidents of attacking and killing other fish in aquariums. Accidents occur with human hands as well. When looking at total dangerous encounters involving piranhas, the red-bellied piranhas are at the top of the list.

Are Black Piranhas The Most Aggressive?

Black piranhas are also known as redeye piranhas. The reason why they must be considered aggressive is that they enjoy being more solitary than most other piranha species.

Black piranhas have a tendency to attack and kill tankmates when they are stressed or cramped in a tight setting.

Black piranhas are better to keep on their own. If you only wish to have one piranha in a 25-30 gallon tank, you may enjoy keeping one and only black piranha to avoid attacks and aggression.

Are Caribe Piranhas Aggressive?

All piranhas can get aggressive under stressful situations. The following reasons may cause a Caribe piranha to act out in aggression:

  • poor water quality
  • small tank sizes
  • improper nutrition 
  • aggressive tankmates (eg: cichlids)

The Caribe piranha is also referred to as the Black Spot piranha.  They are found in shallow waters in larger groups. A Caribe piranha is known to attack injured or ill fish. They may also attack each other if there is blood in the water or if food is scarce.

YouTube video

Do Piranhas Eat Each Other?

Piranhas are not as aggressive as you may think. They can be boring in a tank due to their shy, timid and skittish nature. They may get defensive within their own species and attack each other under certain circumstances such as:

  • scarcity of food
  • an open wound or blood in the water
  • territorial disputes
  • a sick or dying piranha is nearby
  • accidentally bitten during a feeding frenzy

Piranhas are not looking to eat each other, but when times are tough, they may seek the opportunity to take a bite. They can be considered cannibalistic in desperate times.

Sometimes accidents occur during a feeding frenzy. One piranha’s fin may get caught in the action and be torn. They may end up being eaten if they can’t flee and recover. A piranha’s fin may grow back.

Why Is The Red-Bellied Piranha The Most Aggressive?

The red-bellied piranha is widely believed to be the culprit of most piranha attacks in captivity. They are the most common in the wild and in aquariums leading to their total attacks being higher than other species.

In the wild, a hungry red-bellied piranha may get more aggressive. They may defend their territory or lash out from extreme hunger.

Usually a larger fish will not be attacked, but during dry season, things can change rapidly. A small gash in a larger can cause red-bellied opportunistic piranhas to team up and attack, feast and kill other fish in their waters.

Red-bellied piranhas prefer to school together out of defense and security instead of attacking as a team. They are known have some of the the sharpest teeth and strongest jaws from all piranhas.

Will My Red-Bellied Piranha Attack Me?

Accidents happen when we least expect it. A hungry red-bellied piranha could easily damage or tear off our fingers if we are not careful. Swimmers have been mutilated or severely wounded.

Wounded animals in the water stand no chance. Any blood in the water will excite them much more. Nonetheless, they are the most appealing and widely available piranha to keep in captivity.

Are All Piranhas Aggressive?

No. Many piranhas like to keep to themselves and do not wish to attack tankmates or humans. They prefer to scavenge or forage for natural sources of food that fall into their rivers and streams from fruit trees. Some piranhas are largely herbivores such as the Tometes Camunani.

Hunger and desperation may cause piranhas to attack, but more often than not, there needs to be blood in the water or severe stress from poor water quality or aggression instigated from tankmates.

How Do I Know If My Piranha Will Attack?

A piranha makes warning sounds to warn us or tankmates to back away. It may sound like a:

  • bark
  • grunt
  • click
  • gnashing of teeth

The sounds increase with frustration and annoyance. The swim bladder inflates and contracts to let out these sounds. This is a fair warning to us and tankmates to leave them alone.

Another reason why a piranha may attack is that there is an injured fish or blood in the water. Remove any injured fish in your tank before it’s too late.

Do Piranhas Defend Their Eggs?

When piranhas breed, a female may lay up to 4000-5000 eggs at a time. The mating pair will guard the eggs for the next 2-3 days until they hatch.

During this time, they will ferociously defend the space with barks, clicks and snaps. Any fish that gets too close could get attacked.


Thanks for visiting HelpUsFish.com for another article on Piranhas that we greatly enjoy taking care of in our aquariums. Check out more of our articles on the variety of aquatic life we research and keep. Bye for now!

Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.