Knifefish

The knifefishes (also knife fishes) are ray-finned fish that are elongated in shape and whose fins run the length of the body, with the resulting appearance of a knife. There are two orders in which they occur; the Gymnotiformes and the Osteoglossiformes. Knifefishes are primarily nocturnal. They are found in the wild in lakes of South America and Africa. They are also popular aquarium fishes.

Knife fishes are weakly electric fish, producing electrical fields for navigation. They have two types of electric receptors, tuberous receptors and ampullary receptors.

Species of knifefish include:

• Black ghost or glass knife fish (Eigenmannia virecens)
• Speckled knife fish
• Clown knife fish (Chitala chitala or Notopterus chitala)
• African knife fish (Kenomystus nigri)
• Banded knifefish (Gymnotus carapo )