Alosa vistonica well-developed teeth on the palatine and vomer, especially in juveniles. Alosa vistonica Alosa vistonica is a species of shad, a freshwater fish in the Clupeidae family. It is endemic to a single shallow lake, Lake Vistonida in Greece. It is classified as critically endangered (CR) and is threatened by sewage, industrial effluents, destruction of spawning sites by agricultural development and increased salinity following the opening of a canal into the sea. It has been suspected to be extinct already. "A. vistonica" reaches a maximum length of 17 cm (SL). It is distinguished from other members of its genus entering freshwater
West African pygmy herring West African pygmy herring The West African pygmy herring ("Sierrathrissa leonensis") is a very small fish, reaching a maximum length of SL, is a member of the herring family Clupeidae, and belongs to a radiation of the subfamily Pellonulinae in the freshwater systems of western and central Africa that includes such species as the "Microthrissa royauxi" of the Congo River basin and "Limnothrissa miodon" of Lake Tanganyika. It is the only species of its genus. A very small fish which shows a reduction in size and some neoteny when compared to its larger relatives. The West African pygmy herring is