A combination of selected substances in paint to prevent the settlement and growth of different bio-fouling organisms with a reduced negative effect on the ecosystems compared to present methods. Useful substances include medetomidine with various copper and zinc formulations, tolylfluanide, diclofluanide, DIURON&trade； and IRGAROL&trade；, or more general biocides such as SEANINE&trade； (4,5-dichloro-2-n-octyl-3(2H)-isothiazolone) or ECONEA&trade； (2-(p-chlorophenyl)-3-cyano-4-bromo-5-trifluoromethyl pyrrole).
