The Unicorn Tang is best known for the long appendage that grows from it?s forehead. The horn usually begins to show up when the fish reaches about 6 ? 9 inches. Unicorn Tangs will spend their day picking at rockwork and occasionally sand in search for hair algae to eat.. They are found widespread throughout the Indo-Pacific from the Red Sea to Japan, the Rapa Islands, Hawaii, Tuamotu, and the Marquesas.. Care should be taken when handling this fish as it?s caudal peduncle is a very sharp non-retractable razor that can inflict a deep and painful cut: a cut from its scalpel can cause discoloration and swelling of the skin with a high risk of infection. The pain lasts for hours then still ends up having a dull ache.