Abstract: An antifouling marine paint having an antibotic active agent which (1) is toxic to gram negative organisms of the genus Oceanospirillum, (2) is relatively insoluble in seawater to permit a slow leaching into the paint-seawater interface, and (3) is non-photolytic, i.e., is not degraded by exposure to sunlight. Further, when used with a copper base antifouling paint, the antibiotic must not be broken down by the copper in the paint. The antibotic may be selected from the group consisting of chloramphenicol, erythromycin, neomycin, and streptomycin.