The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large‐scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.

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Fish can contribute directly and indirectly to nutrient recycling in aquatic environments, affecting community structure and ecosystem processes. Through the excretion of metabolic waste, fish make inorganic nutrients available in the environment that can be used by algae and bacteria. Nitrogen and phosphorus are often limiting nutrients in streams, so fish can be a relevant source of these nutrients. Many factors can influence excretion rates, including diet, body nutrient demand (for reproduction and growth), ontogeny, body size, temperature and other abiotic factors. Currently, two theories propose to explain which factors control excretion rates: 1) The Theory of Ecological Stoichiometry is based on mass balance models and uses the amount of nutrients in the diet and the fish nutrient demand as predictors of excretion rates; and 2) the Metabolic Theory of Ecology that uses body size and temperature as factors that regulate an organism metabolic rates and, thus, its excretion rates. The relative importance of fish as nutrient recyclers in streams varies depending on species intrinsic characteristics and environmental factors. This includes the magnitude of excretion rates from the entire fish community, the nutrient concentration and nutrient input into the stream, the stream nutrient demand and the period of activity and behavior of the fish. For example, species that are abundant in oligotrophic streams have the potential to represent an important source of nutrients. But other peculiarities, such as diet, specific nutrient demands, or migratory behaviors, can make them important sources or sinks of nutrients in a stream. This article reviews studies that address the role of fish as nutrient recyclers and explains the most common techniques used in this type of studies.