Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Alfaro cultratus

Knife livebearer

Alfaro cultratusAlfaro cultratus
Photos by Andy Rapson


Alfaro: Taken from Anastasio Alfaro zoologist of the Natural Museum of Costa Rica.

General Notes:

Alfaro cultratus named after Anastasio Alfaro zoologist of the Natural Museum of Costa Rica.

There common name comes from the sharp edge between their anal fin and tail.

Alfaro cultratus is generally very peaceful and can be kept in a community tank but Alfaro cultratus does best in a species tank , with excellent water circulation. Females give birth to between 10 to 30 live fry which are quite long at 1 to 1,5 cms at birth but are very slender.


Their wild diet consists mostly of insects. In captivity Alfaro cultratus is unfussy and will eat most food offered. Their diet regularly should include some fresh protein such as live or frozen food in order to mimic their wild diet, dried food alone won't keep these fish in top condition.


If breeding is intended then the female should be placed in a separate well planted tank on her own until she gives birth and then removed in order to prevent her from eating the fry. Alfaro cultratus might be sensitive to worsening conditions which will result in poor health.

Wild status

The status of wild populations of Alfaro cultratus has not assessed and is unknown.

Information at a glance

pH: 7 to 8
dGH: 5 to 12
Temperature: 24-27°C  (75-80°F)
Diet: Insectivorous.
Size: 8 cms (3.5 inches)
Min tank size: 100 litres
Difficulty level: Intermediate
Aquarium type: Community / species.
Swimming level: Upper levels and surface

Distribution and habitat

distribution map for Helostoma temminckii

Origin: Central America: Costa Rica, Panama and Nicaragua

Habitat: Small, fast to slow moving rivers, shoreline of large rivers and ditches.


Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cyprinodontiformes
Family: Poeciliidae
Genus: Alfaro
Species: Alfaro cultratus (Regan 1908)

Common name:
Knife livebearer

Synonyms: Alfaro acutiventralis, Petalurichthys amazonum, Alfaro amazonum, Petalosoma amazonum, Petalurichthys cultratus, Petalosoma cultratum