Smalltail Pencil Wrasse

Geographical Origin and Habitat: Endemic to the Hawaiian Islands in the central Pacific Ocean. Inhabits deep seaward reefs, surge channels, and sandy areas adjacent to coral rubble at depths ranging from 15 to over 60 meters.

Taxonomy and Morphology: Member of the family Labridae, genus Pseudojuloides (pencil wrasses). Features an extremely elongated, almost cylindrical body. Possesses a small terminal mouth with protruding teeth for catching micro-crustaceans. Grows to about 10 cm.

Social Behavior: Peaceful, highly timid, and elusive. Lives in small groups consisting of a single male and a small harem of females. They swim rapidly close to the substrate and panic easily.

Coloration and Sexual Dimorphism: Sexual dimorphism is highly pronounced. Males showcase an olive-green to blue body with a bright yellow and blue horizontal stripe running along the side, and a dark tail. Females are uniform bright pink-orange or cherry-red, lacking stripes.

Aquarium Setup: Requires a spacious tank of at least 280 liters with a fine sand bed at least 5-8 cm deep for burrowing, which is vital for sleep and stress relief. A secure, tight-fitting lid is mandatory as they are notorious jumpers.

Diet and Feeding: Carnivorous. Demands frequent feeding, at least 3 times daily. Offer small frozen foods like mysis, copepods, and vitamin-enriched brine shrimp. May be hesitant to accept dry foods initially, preferring live prey.

Water Quality: Pristine and stable marine parameters: temperature 23-28°C, pH 8.0-8.5, specific gravity (SG) 1.020-1.025, GH 15-25, KH 8-12. Highly intolerant to ammonia and nitrite, and sensitive to elevated nitrates.

Compatibility and Cohabitation: 100% reef safe. Entirely peaceful. Best housed with docile tankmates such as gobies and anthias. Avoid territorial or hyperactive swimmers like large surgeonfishes, which can frighten it and cause starvation.

Aquarium Breeding: Protogynous hermaphrodite. No records of captive reproduction due to the high difficulty of keeping breeding groups healthy in the long term.

Risks and Diseases: High shipping mortality rate due to transport stress. Can easily damage its snout by colliding with glass or rocks when startled. Requires a long acclimation period and a threat-free tank to overcome its shyness.