The Ghost Knifefish (Apteronotus albifrons), also known as the Black Ghost Knifefish, is a striking and highly intelligent freshwater species native to the rivers and floodplains of South America. Distinguished by its elongated, blade-like body and graceful, undulating movement, this nocturnal fish uses a weak electric field for navigation and communication. It is a popular choice for experienced aquarists due to its unique appearance, complex behaviour, and compatibility with larger, peaceful tank mates. Features of a Ghost Knifefish Long, laterally compressed body with smooth, scaleless skin Jet-black coloration with white markings on the tail and snout Moves using a continuous fin along the underside of the body Uses electric fields for navigation and detecting prey Typically reaches 3050 cm in length when fully grown The Best Aquarium Size for Ghost KnifefishDue to their large adult size and active swimming habits, Ghost Knifefish require a minimum aquarium size of 350 litres. A longer tank is essential to allow adequate swimming space, and a secure lid is a must, as they are known jumpers. They prefer subdued lighting and appreciate plenty of hiding spaces. Tank Mate Compatibility for Ghost KnifefishGhost Knifefish are best kept with calm, non-aggressive tank mates of similar size. Suitable species include: Silver Dollars Severum Cichlids Angelfish Rope Fish Clown Loaches Diet for Ghost KnifefishCarnivorous by nature, Ghost Knifefish thrive on a diet of high-quality frozen or live foods such as bloodworms, brine shrimp, blackworms, and chopped earthworms. They may be trained to accept sinking carnivore pellets. Feed them after lights-out to match their nocturnal feeding habits. Aquarium Setup for Ghost Knifefish Aquarium FiltrationUse a powerful external canister filter to maintain excellent water quality. Low-flow settings are preferred, as Ghost Knifefish are not adapted to strong currents. Aquarium PlantsLive or artificial plants can be used to provide shelter and reduce stress. Choose sturdy, low-light species like Java Fern or Amazon Sword. Aquarium LightingDim lighting is ideal. Use subdued or adjustable LED lights to simulate their native low-light environments and promote natural behaviours. Aquarium HeatingMaintain water temperature between 25C and 28C. Consistent warmth is critical for their health and immune function. Aquarium SubstrateSoft sand or fine gravel is recommended to prevent damage to their scaleless skin. Avoid sharp or abrasive materials. Aquarium DecorationsProvide plenty of hiding spaces using driftwood, PVC pipes, caves, or rock tunnels. Ghost Knifefish are shy and require secure shelters, especially during the day.