Wikipedia
FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web. Over time it has "evolved into a dynamic and versatile ecological tool" that is widely cited in scholarly publications.
FishBase provides comprehensive species data, including information on taxonomy, geographical distribution, biometrics and morphology, behaviour and habitats, ecology and population dynamics as well as reproductive, metabolic and genetic data. There is access to tools such as trophic pyramids, identification keys, biogeographical modelling and fishery statistics and there are direct species level links to information in other databases such as LarvalBase, GenBank, the IUCN Red List and the Catalog of Fishes.
, FishBase included descriptions of 32,900 species and subspecies, 304,500 common names in almost 300 languages, 55,300 pictures, and references to 51,600 works in the scientific literature. The site has about 800,000 unique visitors per month.