Vampire Fish

Hydrolycus armatus

Photo of aquarium fish Vampire Fish
Natural range
  • South America area
Predators CharacinsConservation status: Least concern LC

Family:Cynodontidae

Other scientific names: Hydrocyon armatus

The Vampire Fish, or Payara (scientific name Hydrolycus armatus), belongs to the family Cynodontidae. This species is one of the largest predators inhabiting the river systems of South America. It is not suitable for keeping in typical home conditions, requiring very large aquariums, available only in large private collections or public institutions.

Required aquarium volume
2000 L
Size in aquarium
60 – 100 cm
Temperature
24 – 28 °C
Temperament
Predator (dangerous to small, incompatible)
Parameters
Temperature24 – 28 °C
Water pHSlightly acidic (6) – Slightly alkaline (8)
Water dHSoft (5) – Hard (15)
Water salinityno salt (freshwater)
Size in aquarium60 – 100 cm
Lifespan10 years
TemperamentPredator (dangerous to small, incompatible)
Toward small fishpredator
Required aquarium volume2000 L
Lightingmoderate (regular)
Substraterocky (rock formations, boulders, etc.)
Water flowstrong
FeedingFor carnivores (live fish, insects, etc.)
CareSolitary

Frequently asked questions

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

How big does Vampire Fish get?

An adult reaches 60–100 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Vampire Fish need?

The minimum recommended volume is 2000 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Vampire Fish need?

Temperature 24–28 °C, pH 6–8, hardness 5–15 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Vampire Fish live?

Around 10 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Vampire Fish aggressive?

Temperament: predator (dangerous to small, incompatible). This is a predatory species — any fish small enough to fit in its mouth will eventually be eaten.

How many Vampire Fish should be kept together?

Recommended setup: solitary. Ignoring this is a common cause of stress and disease.

What does Vampire Fish eat?

Diet type: for carnivores (live fish, insects, etc.). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Vampire Fish?

The scientific name of the species is Hydrolycus armatus, family Cynodontidae. It also appears in the literature as: Hydrocyon armatus.

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