Larvae of the genus Contracaecum can be found in several species of fish. This study aims to analyze the prevalence, incidence and average abundance of Contracaecum sp. in fish, and to relate host species richness to parasite abundance. A total of 2888 specimens of host fish were collected, and only 217 specimens showed Contracaecum sp. infections. A total of 64 species of fish were collected, in which the greatest richness of hosts was evidenced during the dry season. During the dry season, the highest prevalence values ​​of Contracaecum sp. were found in Erythrinus erythrinus (P=43.18%) and Acestrorhynchus sp. (P=17.39%).  The values ​​of high abundance (AM= 0.73) and average intensity (IM= 9.77) were evidenced in Sorubim lima. During this period, the relationship between host richness and occurrence of Contracaecum sp. was also significant. In conclusion, the study showed the...