Three Spot Damselfish

Geographic Origin and Biotope: Widespread in the Indo-Pacific, from the Red Sea and East Africa to Line Islands, Japan, and Australia. Inhabits lagoon and seaward reefs down to 55 meters; juveniles often commensally shelter in large sea anemones.

Taxonomy and Morphology: Member of the Pomacentridae family. Grows significantly larger than most other damselfish, reaching a maximum length of 14 cm (5.5 inches).

Social Behavior: Exceptionally aggressive. Schooling as juveniles around anemones, they transition into highly territorial, combative solitary adults that defend large reef patches.

Coloration and Sexual Dimorphism: Juveniles are solid jet-black with three distinct white spots (one on the forehead, one on each side). As they mature, the black turns to a dull charcoal-grey, and the white spots fade or disappear. No obvious sexual dimorphism.

Aquarium Setup: Requires a relatively large tank of at least 280 liters for adult specimens. Needs sturdy rockwork with distinct territories and ample swimming space.

Diet and Feeding: Voracious omnivore. Readily eats frozen foods (mysis, brine shrimp, krill), high-quality dry flakes, pellets, and algae-rich foods.

Water Quality: Highly adaptable to varying water conditions. Target parameters: temperature 24-27°C (75-81°F), pH 8.1-8.4, specific gravity 1.020-1.025, GH 15-25, and KH 8-12.

Compatibility and Tankmates: Reef-safe with corals. Highly incompatible with peaceful or small community fish. Best kept with large, aggressive tankmates (triggerfish, groupers, large tangs).

Aquarium Reproduction: Feasible. Spawning occurs on rocks cleaned by the male, who guards the adhesive eggs tenaciously until they hatch.

Risks and Diseases: Extremely hardy. The primary risk is extreme territorial aggression towards other tank inhabitants, often causing physical harm.