Ecological risk assessments are often limited in their ability to consider metabolic transformations for fish species due to a lack of data. When these types of evaluations are attempted they are often based on parent chemical only, or by assuming similarity to available mammalian metabolic pathways. The metabolism maps for five pesticides (fluazinam, halauxifen-methyl, kresoxim-methyl, mandestrobin, and tolclofos-methyl) were compared across three species. A rapid and transparent process, utilizing a database of systematically collected information for rat, goat, and fish (bluegill or rainbow trout), and using data evaluation tools in the previously described metabolism pathway software system MetaPath, is presented. The approach demonstrates how comparisons of metabolic maps across species are aided by considering the sample matrix in which metabolites were quantified for each species, differences in analytical methods used to identify metabolites in each study, and the relative amounts of metabolites quantified. By incorporating these considerations, more extensive rat and goat metabolism maps were found to be useful predictors of the more limited metabolism of the five pesticides in fish.