All About Knifefish

Knifefish are long and slender like knives – and some of them are quite "electrifying"!

All About Knifefish All About Knifefish - Photos (TL-BR): Vladimir Wrangel, boban_nz, tristan tan, Vladimir Wrangel/Shutterstock

What Are Knifefish?

There are two groups of knifefish: the Old World knifefish found in Africa, India, and Southeast Asia, and the New World knifefish located in South and Central America. Most have an elongated body and lack pelvic fins. As a result, they move forward in a wave-like motion. Their habitat includes lakes or slow-moving rivers. They hunt at night for fish or other aquatic creatures. Electric eels can even generate electric fields to stun their prey with electric shocks.

Main Characteristics of Knifefish

1. They Lack Pelvic Fins

Most knifefish either have no pelvic fin at all or possess a long, thin fin that stretches from the belly to the end of the body.

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2. They Have Feather-Like Fins on Their Back

On their back, some have a very thin, narrow fin that extends along the entire back to the tail fin. It resembles a feather. This is why many species are called featherbacks.

3. Many Knifefish Can Generate Electricity

Within the New World knifefish, there is the family of naked-back knifefish with about 50 species. All of them can produce electric fields. This ability helps them navigate through murky waters, locate prey, and communicate with each other. The most famous among them is the electric eel. It can generate electric shocks that not only stun its prey but also kill it.

Knifefish Family Tree

Amazing Facts About Knifefish

There are 260 types of knifefish.
They belong to the bony fish.
Knifefish are divided into two groups: knifefish and featherbacks.
Even though knifefish and featherbacks aren't closely related, they share some similar features.
Both groups are named because their body shape looks like a knife, except for the electric eel.
They also have a similar way of moving through the water.
The most well-known are the electric eel and the clown featherback.
Featherbacks can be found in Africa, India, and Southeast Asia.
Knifefish live in South and Central America.
Knifefish are carnivores.
They're found in freshwater environments.
The largest knifefish is the electric eel, which can grow up to 8.2 feet (2.5 meters) long.
The smallest knifefish is the Microsternarchus brevis, measuring only 2.1 inches (5.3 cm).