TankBud

Blackbar soldierfish

Myripristis jacobus

Also known as Blackbar squirrelfish, Jacob's soldierfish, Blackbar soldier, Atlantic soldierfish

SaltwaterFish

Blackbar soldierfish (Myripristis jacobus)
Pauline Walsh Jacobson · CC BY 4.0

Care at a glance

Temperature
73–81°F
23–27°C
pH
8.0–8.4
Adult size
8.7 in
22 cm
Minimum tank
79 gal
300 L
Temperament
Mostly peaceful
Social behavior
Social
Tankmates
With caution
Swim level
Middle
Difficulty
Easy
Breeding
No record
Rarity
Common
Reef safe
Reef safe with caution
Family
Holocentridae
Origin
Native to the western and eastern Atlantic, sheltering in reef caves and under ledges by day and feeding on plankton at night.

Overview

Keep a blackbar soldierfish, or a small group, in a tank of at least 300 litres with plenty of caves and shaded overhangs, at 23 to 27 C and pH 8.0 to 8.4. It is one of the hardier nocturnal reef fish and adapts well to aquarium food. It is coral safe but will eat very small shrimp and fish, so treat it as reef safe with caution around tiny inverts. It is peaceful and sociable and does best in the company of its own kind. Feed meaty foods such as mysis, krill and chopped seafood, preferably in the evening.

In the wild

The blackbar soldierfish is a rounded red fish with a dark bar just behind the gill cover and large dark eyes for night vision. It packs into caves and under ledges during the day, often in groups, and drifts out at night to feed. Its deep red colour and big eyes make it a classic caves-and-ledges reef fish.

Good to know

Myripristis jacobus reaches around 22 cm and is a plankton feeder, rising off the reef at night to pick drifting animals out of the water. Its large eyes and red colour are typical adaptations to a nocturnal life, since red looks black in dim deep water and hides the fish. It uses its swim bladder to produce clicks and grunts.

Did you know

The deep red colour of a soldierfish acts as camouflage at depth, because red light is filtered out first in seawater, so in the dim caves where it hides the bright red fish actually looks nearly black.

Common questions

What size tank does a Blackbar soldierfish need?

A Blackbar soldierfish needs at least 79 gal (300 L). It spends most of its time in the middle.

What temperature and pH does a Blackbar soldierfish need?

A Blackbar soldierfish is comfortable at 73–81°F (23–27°C) with a pH of 8.0–8.4.

How big does a Blackbar soldierfish get?

An adult Blackbar soldierfish reaches about 8.7 in (22 cm).

Related species