TankBud

Redtail wolf fish

Hoplerythrinus unitaeniatus

Also known as Aimara, Jeju, One-lined wolf fish, Redtail trahira

FreshwaterFish

Redtail wolf fish (Hoplerythrinus unitaeniatus)
Célio Moura Neto · CC BY 4.0

Care at a glance

Temperature
73–82°F
23–28°C
pH
5.5–7.5
Adult size
11 in
28 cm
Minimum tank
66 gal
250 L
Temperament
Aggressive
Social behavior
Solitary
Tankmates
With caution
Swim level
Bottom
Difficulty
Medium
Breeding
No record
Rarity
Very rare
Family
Erythrinidae
Origin
Widespread across much of tropical South America east of the Andes.

Overview

Keep this predator on its own, since it will eat tankmates small enough to swallow and can be rough with its own kind. A single fish needs a tank of at least 250 liters with a secure lid and plenty of cover. It is hardy and tolerant of poor water, but its predatory nature and jumping ability call for a careful setup.

In the wild

Lives in slow and still waters including swamps, ponds, and quiet stream margins, often where oxygen runs low. It is a bottom oriented predator that lurks among cover and ambushes prey. It can breathe air to survive in stagnant pools.

Good to know

Hoplerythrinus unitaeniatus is a wolf fish relative reaching around 28 cm, more slender than the common trahira and marked with a reddish tail and a dark shoulder spot. It can use its swim bladder to breathe air. It belongs to the family Erythrinidae.

Did you know

It can gulp air at the surface and survive in oxygen starved pools that would kill most fish, and it may wriggle overland to reach new water.

Common questions

What size tank does a Redtail wolf fish need?

A Redtail wolf fish needs at least 66 gal (250 L). It spends most of its time in the bottom.

What temperature and pH does a Redtail wolf fish need?

A Redtail wolf fish is comfortable at 73–82°F (23–28°C) with a pH of 5.5–7.5.

How big does a Redtail wolf fish get?

An adult Redtail wolf fish reaches about 11 in (28 cm).

Related species