[Ebook] 500 freshwater aquarium fish – Characoids – Swordtail Characin (Stevardia nisei)

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.

Synonym

• Corynopoma nisei

Family

• Characidae

Subfamily

• Glandulocaudinae

Distribution

• Meta River in Colombia, and possibly in Trinidad.

Size

• Up to 2 3/4in (7cm).

Behavior

• Peaceful shoaler; should not be housed with fin-nipping species such as Barbus tetrazona (Tiger Barb).

Diet

• Wide range of foods accepted.

Aquarium

• 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).

Breeding

• 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.