Twait shad are silvery, sometimes with a bronzy tinge, and there are a distinctive row of six to ten large dark spot just behind the gill cover though these may fade when the fish is dead. The adult length is typically . The twait shad is found in most of Europe and all countries bordering the Mediterranean Sea. "Alosa fallax" has a similar lifecycle to "A. alosa" (allis shad). They are known to live in sympatry. Some studies have suggested "A. fallax" and "A. alosa" species can hybridize. They are anadromous species, like many other species in the genus "Alosa". However, some
Australian herring Australian herring Arripis georgianus, known as the ruff, tommy ruff, Australian ruff or the Australian herring, is one of four Australasian fish species within the genus "Arripis". It closely resembles its 'cousin', the Australian salmon "Arripis trutta", although it grows to a smaller size. Like the other members of its genus, it is found in cooler waters around the southern coast of Australia. It is not biologically related to the herring family Clupeidae. Further vernacular names of this fish in Australia include bull herring, herring, rough, ruffies, sea herring, tommy, tommy rough and South Australian roughy. Ruff is the global