River Tywi these fish to over in weight. In summer and autumn there is also a substantial run of Atlantic salmon ("Salmo salar"). In May the Tywi has a run of the rare and protected twaite shad ("Alosa fallax") and allis shad ("Alosa alosa"). The Tywi also contains brown trout, eels, pike, and a variety of small fish species, and is home to brook lampreys, river lampreys and sea lampreys. The Tywi has the distinction of having accidentally produced by far the biggest fish ever taken on rod and line in fresh water in Britain. This was a sturgeon ("Acipwienser sturio") weighing
Indo-Pacific tarpon living in saltwater, growing just over , while saltwater examples grow over . They live upwards of 44 years and mature within two. They complete their metamorphosis from their larval stage in ten days. They are opportunistic feeders, feeding on smaller fish, crustaceans, and even plants rarely. In saltwater, they mainly feed on prawns and herring, but also many other small fish. In fresh water, no significant difference in their food habits is seen; they eat freshwater prawns and bony bream, mainly. The Indo-Pacific tarpon migrates between the open sea and inland rivers. As with all Elopiformes, it spawns mainly