Tributyltin (TBT) -based coatings have been banned although they are effective to prevent biofouling because they had bad ecology effect for nontarget organism. Since the banned of BTB - based coatings, there are a lot of researches about alternative biocides. Those researches were aimed to study ecological assessments of biocides on aquatic organism. This paper provides information about several methods of biocide toxicity assessment on several aquatic organisms.