The increasing bacterial resistance against antimicrobial agents has induced the search for alternative antimicrobial resources. In this regard, antimicrobial peptides in the fish mucus seem to be usable as therapeutic agents. Antimicrobial effects of the mucus extracts obtained from the skin of various fish species. In this study, the antimicrobial effects of organic and aqueous mucus extracts obtained from the skin mucus of L. bergylta on fish isolates Yersinia ruckeri, Edwardsiella tarda, Listonella anguillarum, Aeromonas sobria, Shewanella baltica, Enterobacter sp., Citrobacter sp. and Escherichia coli, Bacillus subtilis and Lactobacillus plantarum as control strains were analysed. As a result of this study, aqueous mucus extract, aqueous phase and DCM phase that were obtained from the skin mucus of L. bergylta were found not to have any bactericidal effect on the microorganisms tested in this study.