FishBase
A free global online database of fish species, with facts on their names, size, range, biology and uses.
FishBase is a free online encyclopedia of fish, started in 1988 at ICLARM, now WorldFish, by the fisheries scientists Rainer Froese and Daniel Pauly, and now run by a consortium of research institutions. It holds records for more than 35,000 species, with scientific and common names in many languages, maximum length, depth range, diet, distribution maps, photos and links to research. Scientists, fisheries managers and aquarists all use it, and it is one of the main sources for the size and range of fish described on sites like this one.