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.

As its name suggests, giant hogweed it a large umbellifer with distinctively ridged, hollow stems. An introduced species, it is an invasive weed of riverbanks, where it prevents native species…

The silvery dace can be seen gathering in large shoals in lowland rivers and streams. It is a member of the carp family and looks very similar to the chub, but is smaller.

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.

Introduced from Japan in the 19th century, Japanese knotweed is now an invasive non-native plant of many riverbanks, waste grounds and roadside verges, where it prevents native species from…

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.