Common couch is a tall, tuft-forming grass of roadside verges, waste ground and arable land. It is very tough and can shade out more delicate plants. Look for flat, blade-like leaves and thin…

A breeding bird of fast-flowing, upland rivers, the grey wagtail can also be seen in lowland areas, farmyards and even towns in winter.

Living up to its name, the bullhead has a characteristically large, flattened head and a tapering body. Look out for it in fast-flowing, stony rivers and streams.

The tiny, brown-and-white sand martin is a common summer visitor to the UK, nesting in colonies on rivers, lakes and flooded gravel pits. It returns to Africa in winter.

A handsome fish, the tench has olive-green flanks, powerful fins and distinctive red eyes. It can be found in lowland lakes and slow-flowing rivers around the UK.

As its name suggests, Water dock likes damp places, such as the egdes of canals, ponds and rivers. It is a tall plant with large, greenish flower spikes.

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 common clubtail is on the wing in spring and summer. It is an elusive dragonfly that is easiest to see when it first emerges. It can be found along rivers in Southern England and Wales.

The bronze-coloured bream can be seen gathering in large shoals in lowland ponds, lakes and slow-flowing rivers. It is a member of the carp family and looks similar to the dace, chub and rudd.

The red-eyed damselfly is a small, but robust, damselfly of canals, ponds, lakes and slow-flowing rivers. As its name suggests, it has bright blood-red eyes, but a mostly black body.

Nudibranchs, also known as sea slugs, are much like their land-based relatives that you may spot in your garden. But, unlike your regular garden slug, the nudibranch can incorporate the stinging…