The project consists of studying the parasitic communities of fish species such as catfish and scales fish in the Amazon River system. The main points of analysis are the description of these parasitic communities, description of new species and checking whether the size of the host fish has an influence on the abundance of these parasites, their diversity, seasonal variation and their dispersion in the fish. The parasitic communities of different species of fish will be compared, as well as the study on the level of infestation, and the parasite-host relationship in the studied species. This information will be relevant to support strategies to control these parasites in aquaculture production systems.