How can I fish piranhas

Shy, scared and conservative - piranhas as pets

As a piranha owner, you get to hear one question all the time: "What happens when you put your hand into the aquarium?" Many of my fellow human beings believe that the predatory fish with their sharp teeth will come shot immediately and tear the flesh from my hand and arm in a split second. Nothing remains in the imagination of these people except a skeletonized forearm bone.

The rather boring answer to the question what the piranhas do when they see my hand close in front of them is: They swim away. The bloodthirsty predatory fish from the Amazon are actually quite shy. They find human hands rather scary - at best, uninteresting. But admittedly: I also had to learn that first.

The strong underbite is characteristic of the piranha, especially in older specimens

Seven red bellies as roommates

At the beginning of this year it just happened that these extraordinary pets moved in with me: seven specimens of Pygocentrus nattereri, Called Natterers Sägesalmler or simply: Red Piranha. Yes, that's right: These are the predatory fish with the red bellies and shiny golden scales that live in the Amazon in tropical South America. In the wild, several hundred specimens form a swarm and go hunting together.

Piranhas are known for their aggressiveness and their lethal attacks on humans. Allegedly, the predatory fish are supposed to eat whole cows - and people too - alive in lightning ropes. The natural scientist Alexander von Humboldt described the piranha species in 1821 Pygocentrus cariba: "It attacks people while bathing and swimming and often bites off handsome pieces of meat."

The horror stories actually have a core of truth. Swarms of piranha can be dangerous - but only if they are really hungry.

Waiting for prey: the red piranha

Human flesh only in an emergency

When smaller tributaries of the Amazon dry up during the South American dry season, piranhas are caught in isolated pools of water. The predatory fish quickly ate everything that crawls and flies there - then they begin to starve.

After staying in these puddles for weeks or even months, the little guys are so starved that they forget any shyness. As soon as something edible falls into their wet prison, they pounce on it. Then whole cows and people can actually fall victim to them.

The inhabitants of South America know exactly at what times they should avoid which water holes. But when children bathe in rivers where piranhas live, one thing is clear: the fish are not hungry here, and there is no danger. The piranha only eats humans in an absolute emergency, in most cases they only eat other fish, crustaceans and mollusks.

But I also let the horror stories influence me. It was only after three months that I dared to reach into the aquarium without any protective devices to do work there. In the meantime I'm no longer afraid of the little pearly whites. That doesn't mean that you don't have to be careful: A piranha who feels scared or cornered may not bite out of hunger and bloodthirsty, but possibly out of simple self-defense. And if I look at all those sharp teeth like that, it would definitely hurt a lot.

What the piranha does not know, it does not eat

Piranhas are conservative. They don't appreciate change at all. Not even with nutrition.

In the Amazon, piranhas act as health police. They eat sick and injured fish, thus preventing diseases from spreading. They don't seem to be great gourmets.

But aquarium piranhas are more picky, I have found. My seven "predatory fish" do not like everything that I throw into the aquarium for them - regardless of whether it is dead fish, seafood or expensive salmon fillet from the supermarket.

Obviously, piranhas initially only eat what they know. For example, if there is always whole trout for dinner, they will only eat whole trout. It took a good two months to get my piranhas used to their new food: dead smelts from the zoo. They didn't know them from their previous owner. Changes in the aquarium - new plants, roots or stones - seem to be rather critical of them. They prefer it when everything stays as it is.

Only happy in a swarm

Piranhas suffer from stress relatively quickly. They don't like too much light, too light gravel, too much noise and fanfare around the aquarium. They also need plenty of hiding places to retreat to.

You are, however, quite curious. For example, my piranhas like to watch me when I do gymnastics in front of their aquarium. You seem interested.

You are strong with several: Piranhas appreciate life in a swarm

But they are only really happy with several conspecifics. Individual piranhas are prone to panic reactions. They feel most comfortable and safest in a swarm.

However, that does not mean that everything in the troop always goes smoothly. On the contrary: piranhas regularly quarrel and even fight. In doing so, they make - initially irritating - and frightening noises with their swim bladders. They sometimes bite off pieces of their fins in the heat of the moment. However, they grow back quite quickly.

DW reporter Brigitte Osterath is a big piranha fan

Little personalities

Another question I am asked regularly: "Can you tell the individual piranhas apart?" Answer: Yes, of course. Not only are they different sizes, but they all have special body features. Just like probably any other animal.

By the way, piranhas can live up to 30 years old in captivity - older than any dog. And that's why my piranhas all have names: Seamus, Hannibal, Hector, Carlos, Vito, Piet and El Niño.

Piranhas are real character fish. And that's why I like them so much.