There are many books on ‘freshwater fishes’, an internet search yielding literally thousands. Many of these cover fishes of the world, with a fair smattering addressing species encountered in the British Isles and Europe. For many people, the eye bounces off the surface film of Britain's diverse still, flowing, fresh and brackish waters, the mysteries lying below remaining substantially out of sight and so out of mind. Too often, fish are regarded separately from other elements of wildlife. This is a false dichotomy. It is also to the substantial disadvantage of the ways we manage the ecosystems of which they are significant functional elements, as well as prejudicial to humanity in terms of the many benefits that these ecosystems confer upon us. Fish are fascinating, uniquely so but also in these wider ecologically and culturally connected contexts.