- Scientific name: Crenuchus spilurus
- Common name: Sailfin characin
- Group: Characins
- Habitat: South America, Guyana
- Size: 6 cm
- Biotope: They are to be found in the Amazonian River Basins
- Social behavior: A peaceful fish but may be too timid for a community tank. Needs hiding places and is predatory toward smaller species. Male becomes slightly territorial toward his own species and tank-mates.
- Diet: Carnivore, small to large live foods such as mosquito larvae and worms. Also small fish.
- Breeding: Very rare in aquarium
- Tank: Minimum 65 litres
- Population: 1 pair for 70 litres
- Decoration: A small tank with a peat bottom, dense vegetation and hollows are suggested.
- Temperature: 24-28°C
- pH: 5-6,5
- Hardness: 1-5 NK°
- Lifespan: 3-5 years
Description: An elongate fish with a slightly humped back. The body is silver-yellow in colour and iridescent with a defined lateral line. It has a forked caudal and elongated dorsal and anal fins, the dorsal has a trailing filament, more prominant on males. The fins are iridescent, translucent with slight spotting. Male has a longer, red dorsal which ends in a point. Female is smaller, paler.
The Sailfin characin is said to spawn on stones, fanning its eggs. The spawning season is from October to February. The eggs will hatch after 2 days and the fry will be free swimming a few days later. The fry will accept newly hatched brine shrimp immediately and are fast growers.