FishBase
FishBase is a relational database with information to cater to different professionals such as research scientists, fisheries managers, zoologists and many more. FishBase on the web contains practically all fish species known to science: 29600 Species, 222400 Common names, 43600 Pictures, 39200 References, 1410 Collaborators, 25 million Hits/month. With the support of European Union and FAO.
http://www.fishbase.org