The richness of common names of Brazilian marine fishes was studied based on a sample of 725 species, covering 67% of all marine fishes recorded in Brazil. The richness of names is considerable (mean = six common names per species) and is positively related to commercial importance and habitat type, with more names associated with exploited or reef-associated, pelagic, and demersal species. No names were associated with bathypelagic, bathydemersal, and benthopelagic fishes. This richness, while culturally and linguistically interesting, poses a problem for national catch statistics. Some species such as Aspistor quadriscutis, Cathorops spixii, and Genidens genidens were not listed in the catch statistics, but may have been caught for a long time without being recorded. Catches of Sardinella brasiliensis may be higher than what was officially reported, only due to the use of different common names. This may contribute to slow down the recovery process of this collapsed stock. Any attempt to assess the relative impact of different fishing sectors (subsistence, artisanal, industrial, and recreational) on the ecosystem will be undermined by the incomplete understanding of the connection between folk and scientific nomenclature. This issue is even more pervasive when each sector uses its own common name to describe the same species.