1 kinds · tap one for a closer look
Males are territorial and can fight.
339 species in our list are a good match.
Males are territorial and can fight. Keep mid-sized tankmates, as it will eat small fish.
Live and frozen foods, insects and quality flakes.
Tap a food to see what it is.
Males have a gonopodium and extended pelvic (ventral) fins; females are larger and plumper.
Common problems. Tap one to see the signs. This is a guide, not a diagnosis.
Livebearer · Moderate
Easy livebearer that produces young regularly when conditions suit; adults eat fry, so move fry to a separate tank as you find them and feed microworm or powdered flake. Young mature in about 5-6 months.
Keep one male with 3-4 females in a large tank.
Large, well-planted tank with floating plants and hiding spots; warm water.
Warm water and live food.
10-30 young per brood, sometimes many more (Seriously Fish reports 20-100); gestation about 24 days.
Baby brine shrimp, microworms and powdered flake; remove the fry quickly.
A hardy surface-dwelling livebearer from Central America (Honduras to Panama). The 'knife' name comes from a keel of paired, modified scales running from the anal fin to the tail. In the wild adults feed mainly on terrestrial insects. The genus honours Anastasio Alfaro, director of Costa Rica's National Museum.
Charles Tate Regan described this livebearer in 1908. It gets its name from a sharp keel of scales along the underside of the tail.
First described by C. Tate Regan in 1908. Named for 'Cultratus' means knife-shaped.
14 facts checked with sources
Described as Petalosoma cultratum Regan 1908; Petalosoma amazonum and Alfaro acutiventralis are synonyms.
Eschmeyer's Catalog of Fishes: Alfaro cultratusLegacy has no family.
FishBase: Alfaro cultratus summarySeriously Fish 7.5 cm SL (about 9 cm TL); FishBase 7.5 cm TL males and 8 cm females. Larger well-sourced figure is Seriously Fish 7.5 cm SL. Legacy 10 cm too large.
Seriously Fish: Alfaro cultratus · FishBase: Alfaro cultratus summarySeriously Fish 24-28 preferred; FishBase 24-26. Legacy 22-28.
Seriously Fish: Alfaro cultratus · FishBase: Alfaro cultratus summaryLegacy 7-8; both sources give 6.0-8.0.
Seriously Fish: Alfaro cultratus · FishBase: Alfaro cultratus summaryNew value; legacy had none. Seriously Fish 5-20, FishBase 5-12.
Seriously Fish: Alfaro cultratus · FishBase: Alfaro cultratus summaryLegacy 's' (semi-aggressive) fits.
Seriously Fish: Alfaro cultratusLegacy care 2 (moderate); Seriously Fish rates it Easy and hardy.
Seriously Fish: Alfaro cultratusLegacy story lists Costa Rica, Nicaragua and Panama; Catalog of Fishes adds Honduras. 'Atlantic-slope' is from the type locality and river list (Río Iroquois, Sarapiquí, San Juan), not stated outright.
Eschmeyer's Catalog of Fishes: Alfaro cultratus · Seriously Fish: Alfaro cultratus · FishBase: Alfaro cultratus summaryAdds the male's long ventral fins; legacy 'dark gravid spot' not in source.
Seriously Fish: Alfaro cultratusLegacy 10-30 agrees with FishBase; Seriously Fish gives a higher 20-100. Gestation figure added.
FishBase: Alfaro cultratus summary · Seriously Fish: Alfaro cultratusLegacy says the knife name refers to a narrow knife-shaped body; sources tie it to the ventral scale keel (and 'cultratus' to the knife-shaped lower tail lobe). Legacy male colour claim not checked.
Seriously Fish: Alfaro cultratus · FishBase: Alfaro cultratus summary