The Bleak (Alburnus alburnus), is a small fish that resembles a Silver bream and Sardine. In Sweden, its roe is used as a kind of caviar. They are lively in the summer time and dash here and there in pursuit of Insects or Crustaceans. Bleak swim in huge shoals, usually in the surface and sub-surface layers and live in clean, slow moving rivers and streams. They form the staple diet of many freshwater predators.The ultimate skill in fly-fishing is to catch bleak on the fly, as their speed of rejection of a fly-hook is quite astonishing.