Jiujiantang eats seaweed the best. Jiujiantang is generally distributed in the coral reef waters of the western Indian Ocean, with an oval shape and a flat side. Jiujianhang is in an endangered state in the tropical climate zone. The general reproduction method is group spawning type, and the maximum body length is about 11cm.

The body of Jiujian is white, and the head is narrower than Eye-diameter black eye band, extending only down to opercular margin, snout and base of pectoral fin with irregular black spots. There are 8 black vertical bands between the back of the operculum and the caudal peduncle, hence the name Jiujianhang. The pelvic fins are white, the remaining fins are light blue, and the tail spines are grayish white.