Knifefish may refer to several knife-shaped fishes: The Neotropical or weakly electric knifefishes, order Gymnotiformes, containing five families: Family Gymnotidae (banded knifefishes and the electric eel) Family Rhamphichthyidae (sand knifefishes) Family Hypopomidae (bluntnose knifefishes) Family Sternopygidae (glass and rat-tail knifefishes) Family Apteronotidae (ghost knifefishes) The featherbacks, family Notopteridae. The aba, Gymnarchus niloticus Four other unrelated fish species not in any of the above families: Grey knifefish, Bathystethus cultratus. Blue knifefish, Labracoglossa nitida. Collared knifefish or finscale razorfish, Cymolutes torquatus. Jack-knifefish, Equetus lanceolatus.
See also Knifefish (robot), an American military robot