Lesser knob coral

Widely distributed in the Indian Ocean and the Pacific. In Japan found in Chiba Prefecture, Shizuoka Prefecture, Izu Islands, Amami Islands and Ryukyu Islands. They form a disordered hemispherical shape with rows of tiny 3mm in diameter polyps. They can grow in various environments including reef ponds, reef slopes, and even in deep waters. This type of coral is more commonly seen in high latitudes than coral reef areas.