The White-clawed crayfish is a freshwater, bronze-coloured crustacean with pale undersides to its claws - hence the name. It is under threat from an invasive and introduced species of crayfish.…

The Atlantic salmon spends most of its life at sea, but makes an epic journey back to the river or stream in which it hatched to spawn. Look out for it in freshwater rivers in the north and west…

A common and diminutive fish, the minnow can be found in freshwater streams, rivers and lakes across the country. Look out for the dark stripe along its flank and the red bellies of the males.

A fierce predator of small fish and flying insects, the brown trout is widespread in our freshwater rivers. It is has a golden body, flanked with pale-ringed, dark spots.

The river lamprey is a primitive, jawless fish, with a round, sucker-mouth which it uses to attach to other fish to feed from them. Adults live in the sea and return to freshwater to spawn.

Planaria are flatworms in the phylum Platyhelminthes with amazing regeneration abilities giving them the title 'immortal under the edge of a knife'. There are many different species that…

The eel is famous for both its slippery nature and its mammoth migration from its freshwater home to the Sargasso Sea where it breeds. It has suffered dramatic declines and is a protected species…