This bumpy shell lives up to its name and lives partly buried in the seabed along the west coast of Great Britain.

A bushy brown seaweed that appears bright blue underwater.

Look for Water avens in damp habitats, such as riversides, wet woodlands and wet meadows. It has nodding, purple-and-orange flowers that hang on delicate, purple stems.

Look for wood avens along hedgerows and in woodlands. Its yellow flowers appear in spring and provide nectar for insects; later, they turn to red, hooked seedheads that can easily stick to a…

One of the longest seaweeds native to the UK, thongweed helps create a beautiful underwater forest to rival that of any on the land!

The branching, finger-like projections of this fungus give it the appearance of an underwater coral. Its striking colour and form make it easy to spot, but it is scarce in the UK.

The chocolate-brown, plump dipper can often be seen bobbing up and down on a stone in a fast-flowing river. It feeds on underwater insects by walking straight into, and under, the water.

The little grebe is a fantastic diver, but to help it swim underwater, its feet are placed towards the back of its body, making it rather clumsy on land. It only really comes ashore to breed.

An underwater predator, the Saucer bug uses its front pincer-like legs to catch its prey. It can be found at the bottom of muddy, weedy ponds; but handle with care - it can inflict a painful bite…