Abstract
The ictiofauna from Neotropical Region is the richest in the Word. Among 13,000 estimated freshwater fish species, about 6,000 are found in the Neotropical Region and some estimative suggest that this number may reach 8,000 species. Recent studies have proposed the use of the mitochondrial gene Cytochrome c oxidase subunit I (COI) as a global system for identification of all living specie…