Killer catfish? It may sound like something out of a horror movie, but a recent study has found that venomous catfish are surprisingly common in South American rivers.

The study, published in the journal Frontiers in Zoology, found that around 14% of catfish species in the Amazon and Orinoco basins possess venomous spines. This makes them one of the most diverse groups of venomous vertebrates on Earth.

The catfish use their venom to stun or kill prey, and it can also be harmful to humans. In some cases, catfish stings have even been known to be fatal.

What Makes Catfish Venomous?

Catfish venom is produced by glands located at the base of their dorsal and pectoral fins. The venom is then injected into the victim through a series of sharp spines.

The venom itself is a complex mixture of proteins, peptides, and other chemicals. These compounds work together to paralyze prey and cause tissue damage.

The severity of a catfish sting depends on the species of catfish and the amount of venom injected. However, even a small amount of venom can cause significant pain and swelling.

In some cases, catfish stings can also lead to more serious health problems, such as:

* Anaphylaxis: A severe allergic reaction to catfish venom

* Rhabdomyolysis: The breakdown of muscle tissue

* Neurological damage

* Death

Which Catfish Species Are Venomous?

There are many different species of venomous catfish, but some of the most common include:

* Pimelodus pictus: This catfish is found in the Amazon and Orinoco basins. It has a maximum length of about 2 feet and is known for its aggressive behavior.

* Brachyplatystoma capapretum: This catfish is found in the Amazon basin. It has a maximum length of about 4 feet and is known for its sharp teeth.

* Phractocephalus hemioliopterus: This catfish is found in the Amazon basin. It has a maximum length of about 6 feet and is known for its powerful venom.

How to Avoid Catfish Stings

If you are planning on swimming or fishing in South American rivers, there are a few things you can do to avoid catfish stings:

* Wear protective clothing: Wear shoes, long pants, and a long-sleeved shirt to protect your skin from catfish spines.

* Be aware of your surroundings: Catfish are often found in murky water, so be careful where you step and swim.

* Avoid contact with catfish: If you see a catfish, do not try to touch it or catch it.

If you are stung by a catfish, seek medical attention immediately.