Knife livebearer

Alfaro cultratus

Silver-gold flanks and a ventral keel, rather than a tail sword.

A female has an upturned snout, rear-set dorsal and ordinary anal fin. The keel lies behind the anal base.

Natural habitat: Found in lowland creeks, ditches and river margins, usually in slow to moderate flow, with records also from fast rainforest streams.

Grows to 7.5 cm SL. Suits 24–28°C, pH 6–8 and 5–20 dGH.

Appearance and identification

Compare hellerii: its male sword extends the tail fin, whereas cultratus has a ventral keel. Female swordtails also lack that sword.

Conspecific aggression is possible. Keep upper swimming space, cover and separation options.

Offer varied dry, frozen and live foods.

Best in a species tank or with robust, similar-sized companions.

Floating plants and dense cover can accompany open water.

Sources