Freshwater pearl mussels spend their adult lives anchored to the river bed, filtering water through their gills and improving the quality of the water for other species.

With a silvery body, and purple, pink and bluish streaks down its flanks, the rainbow trout lives up to its name. Popular with anglers, it is actually an introduced species in the UK.

The spiky, silvery leaves of Sea-holly give this plants its common name. Look for its beautiful, thistle-like, blue blooms on coastlines and sand dunes in summer.

The silverfish is so-named for its fish-like way of moving and its silvery scales. It can be found in the damp corners of the house, such as the kitchen or bathroom. Infestations can cause serious…