The black ghost knifefish, Apteronotus albifrons, is a tropical fish belonging to the ghost knifefish family (Apteronotidae). They originate in South America in the Amazon Basin in Peru and from Venezuela through Paraguay in the Paraná River. They are becoming popular in aquaria. The fish is all black except for two white rings on its tail, and a white blaze on its nose, which can occasionally extend into a stripe down its back. It moves mainly by undulating a long fin on its underside. It will grow to a maximum length of 20 in (50 cm). It does not have scales.
Black ghost knife fish are nocturnal. They are a weakly electric fish which use an electric organ and receptors distributed over the length of their body in order to locate insect larvae.
The black ghost knifefish natively lives in fast moving, sandy bottom creeks in a tropical climate. South American natives believe that the ghosts of the departed take up residence in these fish, hence the name.
The black ghost knifefish is a weakly electric fish as a result of the electromotor and electrosensory systems it possesses. While some fish can only receive electric signals, the black ghost knifefish can both produce and sense the electrical impulses. Electrogenesis occurs when a specialized electric organ found in the tail of the fish generates electrical signals, which are thus called electric organ discharges (EODs). Then, for these EODs to be sensed by the fish, electroreception occurs when groups of sensory cells embedded in the skin, known as electroreceptor organs, detect the electrical change. The EODs are used for two major purposes: electrolocation and communication.