There are approximately 42 native species of freshwater fish in the UK and a number of marine species that venture into mainland waters for breeding purposes, such as the Atlantic salmon and European eel.
Fish have adapted over millions of years to suit the various freshwater habitats and niches available – some flourishing in the sedate pond and lake environments and others experts in the fast moving habitat or streams and rivers.
The smallest fish you can find is the Ten-spined spickleback (weighing a minute 20g) and the largest is the Atlantic sturgeon (weighing up to 400kg). The most widespread species found across the streams and rivers of the UK is the Brown trout with the Three-spined stickleback being found in the widest array of habitats – from pools to ditches.
Our friend Jack Perks has spent a lot of time filming the freshwater fish species of the UK and has published a book full of photographs of all the species you may find.