Are piranhas dangerous? Well, piranhas are much less dangerous to humans than electric eels or sharks. Aquarium hobbyists that enjoy frightening fish even keep piranhas as pets. But what if you encounter them in the wild? Can a piranha eat a human if provoked?
Are Piranhas Dangerous?
For the most part, piranhas are not dangerous to humans. They are very well equipped to be a threat to us. Yet they almost never attack people.
Jeremy Wade of River Monsters performed an amazing stunt a few years ago. He took a swimming pool full of piranhas and added a bit of blood to the water. Enticing them with the smell.
Next, he feeds the piranhas with a bit of meat on a string. Proving that they are plenty hungry and able to tear chunks out of flesh.
And then he enters the pool in shorts. What do the piranhas do to him?
As it turns out: nothing at all. The school of piranhas remains at the other end of the pool most of the time. They do move close as Jeremy stays still. But not once do they try to bite or attack as a school.
River Monsters viewers and internet commenters took this as proof that piranhas are harmless. Simply a fish with big teeth that pop culture has made into a monster.
Yet that’s not the entire truth of the matter…
Piranha Attack on Humans
You won’t see videos of piranhas eating a human. Nor real piranha attack videos because this almost never happens. The Amazon River has few major cities, but Manaus, Brazil, is one of them.
Over 2 million people live here, with dozens of public beaches and swimming holes. Well within the habitat range of fish piranha. Attacks are very rare here.
That said, the news does report on piranha attacks in South America every year. These events happen at random when conditions are right.
Sometimes large groups of people are attacked, all at once. The New York Post reports that in December 2013, over 70 people were injured by a school of piranhas in Rossario, Argentina.
The attack took place during a heat wave with temperatures over 100 degrees. Crowds escaped into the nearby Paraná River to cool off. The heat had caused water temperatures to rise and river levels to fall. Conditions that cause piranhas to become far more aggressive than normal.
People also do die from piranha attacks. January 2022 was a sad time for Itá Enramada, Paraguay. Here, 4 people were killed from piranha bites to the face and throat. We will never know the entire story of this piranha attack on humans.
It’s worth noting that the actual cause of death was drowning, not blood loss. The surprise of the injuries caused the swimmer to panic, inhaling water and suffocating. It’s also likely that several of the bites occurred after death as the piranhas closed in to feed.
But given the location and severity of each piranha bite, that may be splitting hairs.
It’s clear that piranhas eating a human is well documented. And it even happens semi-often in South American rivers.
What Will Cause a Red Bellied Piranha Attack?
Piranha attack on humans happen most often when the following conditions occur:
- High water temperatures
- Low water levels
- People splashing around
High Water Temperatures
If you are an aquarium fish keeper, you may have seen your pets hanging around near the surface at times. How much oxygen dissolved in water depends on the temperature. Warm water holds less oxygen than cold water does.
Oxygen levels also vary depending on the depth of a body of water. The air will hold up to 100 times the amount of oxygen that water does. Since oxygen dissolves at the water-air surface boundary, fish come here to breathe when the water gets too warm and stagnant.
It’s dangerous for them since a bird or other predator may pick them off. But it’s that or suffocating in deeper water. If you have any shallow ponds in your area, try visiting them on a hot summer day. You will often see fish hanging near the surface where oxygen levels are high.
Low Water Levels
Piranhas are forced to the surface when oxygen levels are low in hot conditions. Low water levels then force them in close proximity to one another. What looks like a pool of brown water in a slow-flowing river may contain hundreds of piranhas. The fish are hidden by the suspended silt and already stressed by low oxygen levels.
Low water levels also make it harder for piranha fish to find the small fish, corpses, fruit, and seeds they eat. They become ravenous, ready to pounce on anything that might be edible.
People Splashing Around
Let’s face it: humans are not graceful in the water. Not compared to fish, anyway. We need to thrash our arms and legs around in order to swim. But this thrashing motion is just what piranhas look for in a meal.
Splashing is what injured, sick, or dying animals do in the water. It’s a loud advertisement of one’s location that a healthy fish would not do. As land animals, this isn’t so obvious to us humans. But the water is an excellent conductor of sound and pressure waves.
Fish have ears for hearing sound waves. But they also have a lateral line: a series of nerves and fluid filled canals that detect subtle changes in pressure.
The sound and pressure waves we make when swimming scream “look here: meal time” to a school of stressed and starving piranha fish. As a result, most piranha bites happen around the arms, hands, legs, and feet of the victims. Where splashing is most intense.
You will notice in the River Monsters video I shared earlier, Jaremy Wade was very careful in how he entered the water. He did so slowly and did not splash around. He just sat still in the water for a while.
The water level was high. As were oxygen levels since the piranhas stayed near the bottom. In short, he was as safe as anyone would be in a pool full of piranas.
Understanding Piranha Fish
Piranhas are one of the most awesome yet misunderstood fish in the world. They are members of the family Serrasalmidae. Piranha fish are close cousins of tetra fish, which might sound outrageous until you take a moment to study their body plan.
Piranhas have a fatty adipose fin, forked tail, and a jaw full of sharp teeth. So do neon tetras, in fact. If you study any pet tetra fish, you’ll see that it’s just a tiny, colorful, toothy piranha. They just happen to prey on worms instead of people.
The other members of the family Serrasalmidae include pacus and silver dollar fish. These fish are as toothy as a piranha – yet they feed on vegetation, fruit and seeds. Pacus even eat tree nuts when the Amazon river floods the surrounding forest; one of the few fish that do so.
Piranha Bite Facts
Piranha teeth are about 4 millimeters long and interlock with one another when the fish closes its mouth. They have 10 teeth in each jaw and robust jaw bones to focus the power of their powerful bite muscles.
When a piranha bites human, people often report that they don’t feel the attack happen. The teeth leave such a clean wound that the pain is delayed. Despite this, piranha fish are known to sever fingers and toes when attacking humans.
Do Piranhas Eat Other Fish?
Other fish are a major part of the diet of wild piranhas. Since they are carnivores, feeder fish are often fed to pet piranhas as well. Their large, sharp teeth let them eat fish of any size.
Fish and other kinds of seafood are best for a piranha. Seafood is lower in fat and fibrous proteins than bird or mammal meat. Making it easier for a piranha to digest and more natural.
Do Humans Eat Piranhas?
Yes, we do eat piranhas. In fact, humans eat piranhas way more often than wild piranhas eat humans. The fish has a delicate white meat that’s low in fatty oils. It is grilled most often but can also be baked, fried, or pan-seared.
3oneseven has an excellent recipe for Brazilian style piranhas. The fish are wrapped in foil and cooked with tomato and lemon. Piranha meat does have tiny bones throughout it, so chew with care.
Since perona fish are carnivores, they aren’t easy to farm raise. They need to eat meat, which is an expensive fish feed. The best farm raised fish are omnivores and herbivores like catfish and tilapia. Not to mention piranha fish are a little dangerous to raise in large numbers.
Conclusion
Piranhas are dangerous when dry season conditions occur. If you go splashing around in a low river full of starving piranhas you may end up with a bite. Or in the worse case, a full-on attack.
Otherwise, piranhas prefer eating smaller prey, animal corpses, and fruit to humans. Piranha fish also only live in South America. So if you aren’t a resident of the continent, you have nothing to fear.
FAQs
People attacked by piranhas report that they sometimes don’t feel the bite right away. But piranhas do remove a lot of flesh when they bite. A large bite will even sever the tip of a finger or a toe. A piranha bite hurts a lot once the initial surprise and shock wears off.
Piranhas are not apex predators; they are prey for lots of river animals. People also catch them and eat them in South America. Piranhas are shy and try to swim away if chased. Even when kept in fish tanks, you have to be careful near their aquarium. Any sudden motions will cause them to dash in a panic. Piranhas will even slam into hard surfaces, losing scales or eyes trying to escape.
