Yellowtail Coris

Geographical Origin and Habitat: Tropical Indo-Pacific, from East Africa and the Seychelles to Hawaii, the Tuamotu Islands, and southern Japan. Inhabits sand-reef zones. Inhabits the warm tropical waters of the Indo-Pacific, commonly found on sandy areas of deep lagoons and seaward reefs down to a depth of about 50 meters.

Taxonomy and Morphology: Labridae family, genus Coris. Reaches 40 cm (16 inches). Elongated body. Juveniles have a bright orange livery with black-edged white saddles, completely different from adults. Features an elongated, flexible body typical of burrowing wrasses. Equipped with strong canine teeth designed to crush the shells of small benthic invertebrates.

Social Behavior: Large, active diurnal swimmer. Buries itself in the sand to sleep or escape danger. Known to flip small rocks and rubble to search for prey. Highly active diurnal fish that spends its day searching the substrate for food. At night or when threatened, it dives headfirst into the sand to sleep or hide.

Coloration and Sexual Dimorphism: Adults are dark greenish-brown with numerous bright blue spots on the body, a red head with green stripes, and a bright golden-yellow tail. Juveniles are orange and white. Undergoes a dramatic color transformation: juveniles are bright red-orange with black-edged white patches, whereas adults develop a dark blue-green body with blue spots and a bright yellow tail.

Aquarium Setup: Requires a very spacious tank of at least 600 liters. A fine sand bed at least 8-10 cm (3-4 inches) deep is mandatory for burying. A secure, tight-fitting lid is essential. Requires a large tank of at least 450 liters (120 gallons) with a deep sand bed of fine, non-sharp substrate (8-10 cm deep) to allow natural burrowing behavior.

Diet and Feeding: Carnivorous. Feeds on hard-shelled invertebrates. Feed chopped whole shrimp, mussels, clams, krill, and premium dry pellets. Carnivorous diet. Feed a variety of meaty foods such as frozen mysis, brine shrimp, chopped krill, clams, and high-quality prepared dry pellets.

Water Quality: Temperature 22°C - 27°C, stable pH 8.0 - 8.5, salinity 1.020-1.025, KH 8-12, GH 15-25. Clean water with high oxygenation is required. Maintain high water quality with efficient filtration: temperature 24-27°C, pH 8.1-8.4, specific gravity 1.020-1.025, and low levels of dissolved organic compounds.

Compatibility and Cohabitation: Carnivorous. Feeds on hard-shelled invertebrates. Feed chopped whole shrimp, mussels, clams, krill, and premium dry pellets. Suitable for tanks with larger, semi-aggressive fish. Not reef-safe with small mobile invertebrates like shrimp, snails, and crabs, which are natural prey.

Aquarium Breeding: Semi-aggressive. Not reef-safe; will consume ornamental shrimp, crabs, hermit crabs, and small snails. Ignores corals but may knock them over while searching for food. Captive breeding has not been achieved. In the wild, they are pelagic spawners, releasing eggs and sperm into the water column where the larvae drift with currents.

Risks and Diseases: Extreme jump risk. When startled, it dives headfirst into the substrate; avoid placing rocks directly underneath the sand to prevent head injuries. Lack of a proper sand bed leads to extreme stress, physical injury, and bacterial infections. The tank must be tightly covered to prevent jumping.