This is one of the so-called glass knifefishes grouped by some authors, along with other related species, within the family Rhamphichthyidae. However, according to the classification followed here (as in Nelson 1994), the Rhamphichthyidae are known as the sand knifefishes and contain only two genera. Green Knifefish look particularly impressive in a shoal, where the establishment of a strict pecking order prevents fighting and, thus, injuries. Steatogenys duidae (elegans) (Barred Knifefish), Sternopygus macrurus (Variable Ghost Knifefish), and various species of Gymnotus, especially G. carapo (Banded Knifefish), all of which have similar requirements, are occasionally available.
- Widely distributed in tropical regions of South America.
- Males reported up to 18in (45cm) but usually smaller; females are considerably smaller.
- Shoaler with crepuscular and nocturnal habits.
- Large livefoods, including live fish, preferred —a factor that needs due consideration prior to purchase; chunky, meat-based or fish-based formulations also accepted.
- Large, well covered, well filtered, well planted, with subdued lighting and large shelters, e.g. substantial pieces of bogwood. A “moonlight” fluorescent tube will facilitate nighttime viewing. Water chemistry not critical, but softish, slightly acid water preferred; quality must be good. Temperature range: 75-86 F (24-30 C).
- Adhesive eggs are laid among floating plants.