The Black Cap Jawfish (Opistognathus randalli) is a species of jawfish native to the Western Pacific. It is known for its distinctive black marking on the head and interesting burrowing behavior.

Distribution and Habitat

Indo-Pacific, found in the Western Pacific from the Philippines to Indonesia, inhabits sandy bottoms near coral reefs at depths of 5-40 meters.

Physical Description

Reaches 10 cm, has a yellowish body with a distinctive black cap on the head, elongated body with large eyes and a large mouth, first described by Smith-Vaniz in 2004.

Diet and Feeding

Carnivorous, feeds on small crustaceans, zooplankton, and benthic invertebrates in the wild, in captivity accepts frozen mysis shrimp, brine shrimp, and prepared foods.

Behavior and Reproduction

Known for excavating burrows in sandy substrates where they retreat when threatened, typically found in pairs or small groups, mouthbrooders with males carrying the eggs.

Aquarium Care

Requires a tank of at least 30 gallons with a deep sand bed of 3-4 inches for burrowing, peaceful toward tankmates but may be territorial toward other jawfish, provide a secure lid as they are known jumpers.

Conservation Status

Classified as Least Concern by the IUCN Red List.