The banded kökopu is a smooth-skinned, largely nocturnal fish that may reside in urban areas where habitat is suitable and they are not often disturbed; often surprisingly close to houses. These fish are only found in New Zealand, living within small tributaries, in slow moving pools. This is usually in native bush where there is sufficient overhead forest cover. They are found throughout New Zealand, but are more common near the coast, and being absent from deforested landscape e.g. intensive agricultural areas such as the Waikato and Manawatu. Their food largely consists of terrestrial insects such as beetles and spiders falling onto the waters surface, where their vibrations caused by their struggles are then detected. They can grow to around 280 mm long, with fish living to more than 10 years old.

Conservation status: Often locally rare, banded kökopu are nationally threatened through habitat destruction and migration barriers.

The largest of our native freshwater fishes, giants may grow to well over ½ a metre and live for more than 20 years. The juveniles are also a member of the whitebait run, and encountered swimming up from the sea late in the season. A stunning maroon fish with gold hieroglyphs covering its body, it is sometimes encountered by eel fisherman in wetlands and swamp lake margins, and is also found in slow flowing streams and rivers. The presence of overhanging vegetation such as native forest or wetland marginal vegetation is very important. They largely feed at night on terrestrial insects falling onto the waters surface, but will readily take small fishes and aquatic insects also.

Conservation status: This awesome fish is seldom seen by New Zealanders today, being notably rare in most areas. It is especially threatened by modification of its forest and wetland habitat, and is often uncommon now even in the suitable habitat that does remain.

By far the most common species found in the spring whitebait run migrating up from the sea, inanga are approximately 10 cm long, and are most commonly found in wetlands, streams, rivers, and lakes with easy access to the nearby sea. As they are fairly tolerant of salt water, they are sometimes also found in tidal estuaries. They prefer slower flowing waters, at the surface of which they may be found hunting at night for terrestrial insects falling on the surface, for aquatic insects, and for zooplankton crustaceans. They have very wide feeding habitats even being known to thrive on cheese in captivity! Inanga rarely live for more than 2 years, usually having migrated and spawned in a lower estuary at the end of their first year.

Conservation status: Fairly tolerant of water quality and habitat modifications, adult populations have been reduced through habitat destruction. Many juvenile inanga are also removed from the declining whitebait catch before they are old enough to reproduce. Many spawning sites located in the estuaries of streams and rivers continue to be destroyed e.g. through grazing of stock to the water's edge.

Play the Whitebait Game!

The dwarf inanga looks like a normal inanga but is much smaller and thinner. Dwarf inanga have one of the most restricted geographical distributions of any New Zealand native fish and are only found in the dune lakes of lower western Northland. Coexisting landlocked with populations of lacustrine common bully and banded kokopu, dwarf inanga school together and feed on zooplankton crustaceans and small aquatic macroinvertebrates such as mosquito and midge larvae.

Conservation status: Although trout predation is considered a threat in some lakes, the factors responsible for the decline of dwarf inanga are unknown in other lakes and it is a threatened species. Gambusia are thought to be a major competitor and aggressor in many of these other lakes and the trout may actually help keep them in check!

Regionally localised to Waikato and Bay of Plenty areas, mudfish historically were found in temporary wetlands and lake margins. They are even found in roadside drains, typically in a temporary water habitat that dries up over summer, with gently flowing waters that are heavily overgrown with vegetation. Their ability to aestivate deep in the mud when their habitat dries up allows them to exist free from competition and predation from other species such as bullies and eels. Mudfish do not go to the sea at any time in their lives. Young mudfish feed on small crustaceans in the water column, whilst adults feed on terrestrial insects and larger aquatic invertebrates with most of their activity occurring under the cover of night. Their length rarely exceeds 90 mm, and they may live for up to 8 years.

Conservation status: Black mudfish are much less abundant and widespread than historically. This is mainly due to widespread drainage and modification of their wetland habitats, largely through conversions to farmland. Much of the more sensitive habitats in which other small populations are found, such as temporarily flooded wetlands, still remain unprotected.