This paper reports on the species of Caligus minimus of the genus Caligus (Siphonostomatoida: Caligidae), parasitic on marine fish, brawn wrasse (Labrus merula), genus Labridae, of Izmir Bay, Aegean Sea. The sea lice, C. minimus, is identified from the gill and external surfaces of the brawn wrasse (total length, 30 cm; weight, 210 gr.), particularly on its head. The entire collection of sea lice consists of 11-12 specimens, all of which are female. Ectoparasitic copepods especially belong to the Caligidae family, the most common crustacean parasites on fish. C. minimus can be found in Atlantic coasts, British waters, the North Sea, and the Mediterranean Sea. C. minimus ectoparasite is a host and mainly recorded on Perciformes, such as Dicentrarchus labrax, Pagellus bogaraveo, Umbrina cirrosa, and Mugil cephalus. Recently, in both sides of the Aegean Sea, C. minimus has been identified from cultured marine fish, mainly D. labrax. The intensity of the infection is apparent on adult fish, especially between winter and early summer. C. minimus is the first record on brawn wrasse caught by gill nets from the Urla coasts in Izmir Bay, Aegean Sea in March 2010.