This basically silver-colored fish has rather unusual distinguishing physical and reproductive characteristics. Mature males possess a long extension of the lower rays of the caudal fin—the “sword” that gives the species its common name. In addition, they have a long, filamentlike extension on each gill cover, with a fleshy structure at the tip; it is believed that this “paddle” is used as a lure to attract a female into the appropriate breeding position.
- Corynopoma nisei
- Meta River in Colombia, and possibly in Trinidad.
- Up to 2 3/4in (7cm).
- Peaceful shoaler; should not be housed with fin-nipping species such as Barbus tetrazona (Tiger Barb).
- Wide range of foods accepted.
- Well planted with ample swimming areas recommended. Water chemistry can range from slightly acid to slightly alkaline and from soft to medium-hard. Temperature range: 72-82 F (22-28 C).
- Unusually for a characin, the eggs are fertilized internally (hence the need for the female to adopt a precise position for mating). The eggs are subsequently released and hatch in 1 1/2 days.