Common name/s: Black Ghost Knife, Ghost Knife, Ghost Ray Scientific name: Apteronotus albifrons Family: Apteronotidae Origin: Amazon River, South America Maximum size: 24 Inches in the wild. Usually not that large in captivity. Care: The Black Ghost Knife requires a tank that it can turn around in which should have a width of 24 inches. Although they can be raised in small tanks, you must upgrade to the BGK's full size eventually. A tank size of 80 Gallons is sufficient. This fish rarely gets over 20 inches long in captivity. The amount of waste this fish produces is low, however a hang-on style filter is still beneficial. They are sensitive to water conditions, they will tolerate pH levels from 6.5 to 8. They do best in temperatures ranging from 75F-82F (24C-28C). Tank mates may include other 'oddball' fish like eels, butterfly fish and the like, however, they are fine with any non aggressive fish that is not seen as food, so larger community fish like Angels, larger Botia species and many more will do fine. Feeding: Black Ghost Knives will usually accept fish flakes, small live fish, chopped earthworms, blood worms, brine shrimp, glass worms, tubifex worms, and beef heart to name a few. Sexing and Breeding: There is no physical way to sex a black ghost knife and not much has been accounted on there breeding behaviour however a courtship is involved before the female lays eggs (Spawning). Comments: The black ghost knife is nocturnal so seeing them all the time is not a common thing. They are also blind and so rely on their sensitive electrical sense to find food and find their way around the tank. The BGK also has a particularly large mouth, so anything that fits in there is under risk of being eaten as BGK's are fish eaters as well. Note: A weak electrical sense guides the BGK around the tank, the fact that two BGK's can be kept in one tank is a controversial one. Usually you must have a larger tank (75Gallon+) to support more then one BGK, however nothing is certain. Photo of the Black Ghost Knives were kindly supplied by 'BlueIce' from this website.