Allis shad Allis shad The allis shad ("Alosa alosa") is a widespread Northeast Atlantic species of fish in the herring family, Clupeidae. It is an anadromous fish which migrates into fresh water to spawn. It is found in the eastern Atlantic Ocean, the western Baltic Sea and the western Mediterranean Sea. In appearance it resembles an Atlantic herring but has a distinctive dark spot behind the gill cover and sometimes a row of up to six spots behind this. It sometimes hybridises with the twait shad ("A. fallax"). This fish becomes mature when three or more years old and migrates to estuaries,
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