Black Ghost Knife Apteronotus albifrons
The Black Ghost can reach up to around 20 inches and has a lifespan of 15 years. Its body is flat and elongated, with a continuous fin along the underside formed by a joining of the caudal and anal fin and moves with an undulating motion. Although they appear clumsy, they have a built in �radar' system that uses low voltage electricity to help them navigate. This and their undulating lower fin allow them to gracefully move forwards and backwards through the aquarium.