Alfaro cultratus

Photo of aquarium fish Alfaro cultratus
Natural range
  • Costa Rica area
  • Nicaragua area
  • Panama area
  • Central America area
LivebearersConservation status: Least concern LC

Family:Poeciliidae

Other scientific names: Alfaro acutiventralis, Alfaro amazonum, Petalosoma amazonum, Petalosoma cultratum, Petalurichthys amazonum, Petalurichthys cultratus

Alfaro cultratus, also known as the knife-edged livebearer, belongs to the family Poeciliidae. This fish is distinguished by its hardiness and unpretentiousness, which means it does not have special requirements for keeping conditions. Although it is not often found in retail chains, this species is quite common among amateur aquarists.

Required aquarium volume
50 L
Size in aquarium
7 cm
Temperature
24 – 28 °C
Temperament
Territorial (often aggressive)
Parameters
Temperature24 – 28 °C
Water pHSlightly acidic (6) – Slightly alkaline (8)
Water dHSoft (5) – Very hard (20)
Water salinityno salt (freshwater)
Size in aquarium7 cm
Lifespan5 years
TemperamentTerritorial (often aggressive)
Toward small fishnot a predator
Required aquarium volume50 L
Lightingmoderate (regular)
Substrateany (no restrictions)
Water flowweak or moderate
FeedingAny (universal)
CareSchooling (usually from 5–6 individuals and more)

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Alfaro cultratus get?

An adult reaches 7 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Alfaro cultratus need?

The minimum recommended volume is 50 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Alfaro cultratus need?

Temperature 24–28 °C, pH 6–8, hardness 5–20 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Alfaro cultratus live?

Around 5 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Alfaro cultratus aggressive?

Temperament: territorial (often aggressive). Keep this in mind when choosing tank mates.

How many Alfaro cultratus should be kept together?

Recommended setup: schooling (usually from 5–6 individuals and more). Ignoring this is a common cause of stress and disease.

What does Alfaro cultratus eat?

Diet type: any (universal). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Alfaro cultratus?

The scientific name of the species is Alfaro cultratus, family Poeciliidae. It also appears in the literature as: Alfaro acutiventralis, Alfaro amazonum, Petalosoma amazonum.

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