Blue Assessor

Geographical Origin and Habitat: Western Pacific, endemic to the Great Barrier Reef and the Coral Sea. Inhabits dark caves, crevices, and vertical drop-offs at depths of 2 to 20 meters.

Taxonomy and Morphology: Member of the family Plesiopidae. Slender, compressed body with elongated fins. Reaches up to 7 cm in length. Famous for its geotropic disorientation, swimming upside-down.

Social Behavior: Peaceful, shy, and shoaling. Can be kept in small groups if introduced simultaneously. Entirely non-aggressive toward other tankmates.

Coloration and Sexual Dimorphism: Body displays a rich, deep blue-purple color with bright blue scale highlights and yellow margins on the fins. Males are typically slightly larger and possess longer pelvic fins.

Aquarium Setup: Requires a minimum tank size of 100 liters with extensive rockwork arranged into caves, arches, and dark overhangs. Prefers moderate to low lighting.

Diet and Feeding: Carnivore. Feeds on zooplankton in the wild. Feed frozen mysis, enriched brine shrimp, cyclops, and high-quality micro-pellets. Feed 2-3 times daily.

Water Quality: High water quality and stability. Maintain temperature at 22-27°C, pH 8.1-8.4, and salinity at SG 1.020-1.025. Prefers gentle water movement.

Compatibility and Cohabitation: 100% reef-safe. Excellent for reef aquariums. Do not house with aggressive fish like dottybacks or territorial damsels.

Aquarium Breeding: Paternal mouthbrooder. The female deposits a sticky ball of eggs which the male carries in his mouth until they hatch.

Risks and Diseases: High jumping risk; ensure the tank is tightly covered. Can starve if housed with aggressive feeders that outcompete it.