Genus Vibrio is involved in common pathologies of aquaculture fish species, being responsible for significant economic losses for that industrial activity. Microalgae and cyanobacteria have demonstrated to count on bioactive compounds able to diminish mortality and morbidity by their use as functional food supply or by addition of those bioactive compounds previously purified. The main goal of this work has been to evaluate the anti-microbian effect (growth of bacterial population measured as changes in optical density) of 25 microalgae extracts on the bacterial strain Vibrio anguillarum CECT 522T. Stock microalgae extracts were obtained from lyophilized biomass treated with methanol 99.9%. A total of thirteen extracts exhibited antibacterial activity. The highest activity corresponded to Monochrysis lutheri, followed by Hemiselmis cyclopea, Porphyridium cruentum, Tetraselmis rubens, Cryptomonas sp, Navicula sp. The anti-bacterial activity was not related to a taxonomic group, indicating species-specific or even strain-specific activity.