Home | Aquarium Livestock | Piranhas, Fish of Myth and Mystery – Part 1 – The Red-bellied Piranha

Piranhas, Fish of Myth and Mystery – Part 1 – The Red-bellied Piranha

Red-bellied PiranhaIt is a calm day on the Amazon River. Two men are fishing in their small wooden boat. As one casts his line, he slips and falls into the water. Instantly, the surface of the water begins to roil and boil with action as a school of flesh-eating piranhas begins to do their nastiest work on the unfortunate fisherman. Minutes later, there is nothing left as the piranhas have eaten their fill. That is the myth. Aggressive and voracious schools of shiny silver and red fish with razor sharp teeth ready to devour anything that touches the water. So how true is that myth? We’ll be talking about the common Red-belly today, and some more commonly seen piranha in my next blogs. 

So how vicious are these fish? And how difficult is it to keep piranha at home? Well, with over 30 species of piranha described it is really all going to depend on which type of piranha you’re talking about and which species you want to keep.

The most commonly seen piranha in the trade is the Red-bellied Piranha, Pygocentrus nattereri. It is a robust, silver fish that can easily reach 6 inches long when mature. Young fish develop the deep red belly that gives them their common name, however, the color on belly often fades or disappears over time. Adults are often completely black or grey. The Red-belly has the most widespread range of all piranha species, found throughout the Amazon River basin where they can gather in large schools. These fish are always searching for their next meal – worms, insects, weakened or injured fish, and even some vegetable matter are all on the menu.  A roaming school is much like a pack of coyotes – any scrap of food will do!

With all of the lore associated with this species, it might surprise some people to learn that these fish are actually very shy and can be rather skittish. In the Amazon, these predators become prey to many others, so hiding and being wary are keys to survival. This “hard-wired” instinct is strong – even a Red-belly that has been kept in captivity for years will retain the urge to stay under cover and avoid being seen. Keeping a small school of Red-bellies does help to reduce their shyness.  To do so will require keeping at least 6 fish in a large (200 gallons or more) aquarium with a very efficient and high capacity filter to keep up with their waste.

Red-bellied Piranha Jawbone” width=Always keep a watchful eye on the group during maintenance – even though they are known to be timid, they do have extremely sharp teeth and will not hesitate to defend themselves if they feel threatened. A bite from a 6 inch piranha can be pretty nasty. Moving slowly and deliberately will help to keep the fish from feeling threatened. Provide them with large pieces of driftwood in the aquarium to reduce stress and give them a place to lurk, hunt and hide.

Let’s face it, piranhas are not the most well-mannered fish when it comes to eating. Red-bellies will wait patiently for something edible to pass by then dash out and take a bite. Tearing at meaty foods with razor sharp teeth can cause quite a mess, so keeping on top of your weekly water changes is going to be essential. Food items can include shrimp, beefheart, pelleted foods, and even some fresh fish filets. Varying the foods will give your fish the best health and deep color. While live feeder fish may make for a spectacular feeding response from piranha, goldfish as a dietary item can cause health issues in predatory fish both inside and out.

Red-bellied Piranhas have a bad reputation, but they can make a fascinating and sturdy pets provided that you are willing to learn about their true habits, provide ample space, and keep the environment as clean as possible.

While the Red-belly is one of the most common species, there are several that are several other species offered from time to time. In my next blog, a species known to be one of the most aggressive and largest species – the Black Piranha.

Until then,


Red-bellied Piranha image referenced from wikipedia and originally posted by Gregory Moine and uploaded by Magnus Manske
Red-bellied Piranha Jawbone image referenced from wikipedia and originally posted by Sarefo


  1. avatar

    My first 75 gallon aquarium held 4 Red Bellied Piranha and a pleco. Only fed guppies once which I never did again. They ate beefsticks with cheese from the local grocery suspended in the tank for 3-4 days at a time. The piranha were my masterpiece in freshwater fish keeping. I am now into saltwater but hope to one day have piranha again as they are a beautiful fish, cool to keep, and low maintenance.

  2. avatar

    wow thanks for the great info… i am currently contemplating purchasing piranhas and just looking around for info first.

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