Blue dot jawfish (Opistognathus rosenblatti) care guide

Group
Marine fish
Family
Opistognathidae (jawfishes)
Origin
Gulf of California (eastern Pacific); sand, rubble and reef areas at about 12 m, in colonies of up to several hundred.
Water
saltwater
Maximum size
9 cm
Temperature
18–21°C
pH
8.1–8.4
Hardness
Salinity SG 1.023–1.026
Minimum tank
115 litres
Care level
expert
Temperament
peaceful
Reef safe
yes

Care

Jawfish dig burrows, so provide a deep bed of mixed sand and rubble (shell fragments and small pebbles) and keep a tight-fitting lid: they jump, especially when frightened. The 115-litre minimum is our estimate; a fine, non-abrasive sand is important. Water: unlike most reef fish it comes from the cooler Gulf of California, and the article links a disease problem to temperatures above 21 °C, rough handling, abrasive substrate and bare-glass tanks. We therefore give 18–21 °C; pH 8.1–8.4 and SG 1.023–1.026 are general marine guidance, not species-specific. A chiller is usually needed. A delicate, costly fish. Brooklynella infections can kill within a day; quarantine is strongly advised. It closes its burrow at night and rebuilds the entrance each morning. Males turn bright white and dart up above the burrow to court females. Sociable with its own kind but defends its burrow. Sources: Wikipedia, List of marine aquarium fish species (en.wikipedia.org/wiki/Listofmarineaquariumfishspecies); Wikipedia (en.wikipedia.org/wiki/Opistognathusrosenblatti). Checked October 2026.

Diet

Feeds on tiny bottom-living and planktonic invertebrates. Offer frozen copepods, mysis, enriched brine shrimp and fine pellets several times a day.

Breeding

A mouthbrooder: after courtship the female briefly joins the male in his burrow, and the eggs are carried in the mouth for about 5–7 days.

Compatibility and tank mates

Reef safe. Keep with calm, peaceful fish and give each jawfish its own patch of sand. It is aggressive only to fish that enter its burrow.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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