Knifefish are tailor-made for careful aquarists who favor unique, somewhat delicate species. Able to navigate, hunt, and even communicate via electrical signals, Knifefish are generally shy and nocturnal. They glide about, forward and backwards, by continually undulating the elongated bottom fin, and are a real pleasure to observe. The show-stopping Black Ghost Knifefish can reach 20” in length, but other colorful and even transparent species remain small. At 5-6 feet in length and packing life-threatening voltage, the famed Electric “Eel’, behemoth of the group, is best left to public aquariums!