Cheilodipterus novemstriatus (Rüppell, 1838), is native to the Indo-Pacific region. These species can be found mostly around the spines of Diadema setosum (Leske, 1778) between 0-40 m in depth. During a scientific diving survey in the Gulf of Iskenderun, a shoal of C. novemstriatus was sighted around a D. setosum. Some photographs of the fish and sea urchin were taken. This is the second study that reports these two species in a symbiotic relationship in Turkish waters. Also, these records show that the Mediterranean coasts are in a rapid tropicalization process, and the Lessepsian species quickly adapt to the Mediterranean.