Regal Anthias

Geographical Origin and Habitat: This species is native to the Southeastern Pacific Ocean, being an exclusive endemic to the Marquesas Islands in French Polynesia. It inhabits steep outer reef slopes and drop-offs at significant depths, typically between 30 and over 60 meters, where light penetration is weak and the water remains cool, clear, and swept by strong currents.

Taxonomy and Morphology: It belongs to the Serranidae family, subfamily Anthiadinae. It features an elongated, laterally compressed body with an elegant lyre-shaped caudal fin equipped with extended filaments. The eyes are large and situated forward, adapted to hunting zooplankton in dim light conditions. Adults reach a maximum size of about 8-9 centimeters.

Social Behavior: It is a peaceful, shy, and highly gregarious fish that forms large, coordinated schools in the wild. They quickly retreat into coral branches when startled. Like most anthias, it exhibits protogynous hermaphroditism, meaning a dominant male maintains a territory and controls an harem of several females.

Coloration and Sexual Dimorphism: The coloration is striking, displaying intense shades of pink, magenta, and violet that merge into golden yellow and orange along the dorsal profile and fins. Sexual dimorphism is highly pronounced: dominant males exhibit far more vibrant colors, elongated dorsal and pelvic fin rays, and longer caudal filaments.

Aquarium Setup: Requires a mature marine aquarium of at least 300 liters, featuring a large open swimming area and plenty of stable live rock arranged to create shaded caves, overhangs, and crevices where the fish can seek shelter. Moderate or dim lighting is preferred to replicate its deep-water habitat, and a secure lid is mandatory.

Diet and Feeding: A strict planktivorous carnivore that needs to be fed 3 to 4 times daily in small amounts. Offer a varied diet of high-quality frozen foods, such as vitamin-enriched copepods, mysis shrimp, brine shrimp, and lobster eggs. It is notoriously difficult to acclimate to dry foods, which may initially be ignored.

Water Quality: Demands pristine and stable water conditions. The temperature should be maintained between 24 and 27 °C, pH between 8.1 and 8.4, and specific gravity stable between 1.020 and 1.025. A powerful protein skimmer and efficient powerheads are recommended to simulate strong, highly oxygenated currents.

Compatibility and Cohabitation: A completely reef-safe species that will not harm corals or sessile invertebrates. It must be housed only with peaceful, non-aggressive tankmates. Avoid active, territorial, or aggressive fish that could easily intimidate this shy species, preventing it from feeding.

Aquarium Breeding: Captive breeding has not been successfully documented in private home aquariums. This is due to their pelagic spawning habits and a complex oceanic larval stage that requires specialized microscopic live feeds not easily cultivated in home setups.

Risks and Diseases: Highly susceptible to stress during transit and acclimation. Under stressful conditions or sudden temperature fluctuations, they are prone to contracting marine ich (Cryptocaryon) or velvet (Oodinium). The primary risk is starvation, making it vital to ensure they are feeding before purchase.