One must always consider the eventual mature size of fish, and if properly maintained this knifefish species will attain close to 20 inches. It is very timid and quiet, but still a natural predator that is nocturnal so any fish under 6 inches may well get eaten. Good tankmates are angelfish, Discus
, and some of the medium but peaceful South American cichlids. And of course the larger (for aquaria) catfish.
The tank must be large, at least 5 feet in length, and 2 feet in width (front to back). The knifefish is inflexible and must be able to turn around in the tank. This sized tank would accomodate one knifefish, plus suitable tankmates. With this large a tank, a group of the afore-mentioned angels or Discus
would be stunning, and since all of these fish prefer very dim waters and occur together naturally, a true biotope aquascape is one possibility, with plenty of wood and branches. Plants, considering the dim light, would be restricted to Anubias
, Java Fern
and Moss (unless one wants to be truly authentic with an Amazonian aquascape) for submersed, but floating plants which would further dim the light would be ideal.