Literature on reproductive behavior and social organization of scorpaeniform fishes is limited. Most information concerns studies of economically important species of the scorpaenid genus Sebastes, with an emphasis on internal fertilization and embryonic development (reviewed by Thresher, 1984). Studies of reproductive behavior of Scorpaeniformes in nature appear to be limited to a few species of pteroine fishes (Fishelson, 1975; Moyer and Zaiser, 1981; Gronell, cited by Thresher, 1984). We know of no field studies of the reproductive behavior of any of the family Congiopodidae. We observed social behavior courtship and spawning of the congiopodid Ablabys taenianotus (Cuvier) at Miyake-jima (34~ 139~ one of the Izu Islands of southern Japan, from September 21 to 28, 1984. Underwater observations, using SCUBA, amounted to 32 manhours. Dives were made 2-3 times daily to (1) census the study population, (2) determine home range sizes and diurnal activities of individuals in the study population, (3) observe social interactions at different times of day, (4) determine the social organization of the species, and (5) observe spawning behavior.