Stephanolepis cirrhifer, commonly known as the thread-sail filefish, is a species of marine fish in the family Monacanthidae. It is found in the western Pacific, in an area that ranges from northern Japan to the East China Sea, to Korea. Other common names for the fish include kawahagi (Japanese) and Jwi-chi (Korean). The fish grows to a maximum length of about 12 inches (30 centimetres), and consumes both plant material and small marine organisms like skeleton shrimp. The first dorsal fin is a strong retractable (folding backwards) spine. The second dorsal fin and anal fin are soft. They have comparatively small pectoral fins and truncated, fan-shaped tail fins. The dorsal and anal fins are colorless. Their second dorsal, anal and caudal fins rounded. In males, 1-3 soft dorsal fin rays extended as filaments; the first ray has a particularly long thread. The fish have a small abdominal spike. The fish are colored from light brown, to grayish- to light greenish-beige, and are slightly patterned with irregular, broken stripes that range from medium brown to blackish.
