Blackbar soldierfish
Myripristis jacobus
Also known as Blackbar squirrelfish, Jacob's soldierfish, Blackbar soldier, Atlantic soldierfish
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
- Swim level
- Middle
- Difficulty
- Easy
- Breeding
- No record
- Rarity
- Common
- Reef safe
- Reef safe with caution
- Origin
- Native to the western and eastern Atlantic, sheltering in reef caves and under ledges by day and feeding on plankton at night.
- Family
- Holocentridae
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.
Where to buy
Some links may not be the exact species or variety.
…or ask your local fish store.
Appears in
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Related species

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Sargocentron diadema6.7 in (17 cm)53 gal (200 L)75–81°F (24–27°C)
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Zebrasoma rostratum8.3 in (21 cm)119 gal (450 L)75–81°F (24–27°C)
Powder Brown Tang
Acanthurus japonicus8.3 in (21 cm)129 gal (490 L)75–81°F (24–27°C)
Scopas Tang
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Sebae mono
Monodactylus sebae7.9 in (20 cm)119 gal (450 L)75–82°F (24–28°C)
