The fly is the second largest river in Papua New Guinea, extending for some 1,000 kilometres and is considered the largest river in terms of water flow per unit catchment area.

The Niugini Bass is found in three major freshwater jungle streams and their corresponding tributaries. They spend most of their time in fresh water and brackish water, a combination of both fresh and salt water. Brackish water has more salt than fresh water and is less salty than the ocean. Tidal movements alter the salinity levels and the mouth of the river. Like the Australian Bass, the Niugini Bass can only be found in a limited distribution. Adverse environmental changes and human events could have a significant impact on their population size.

Like many other non-bass that are called bass, the Niugini Bass prefers cover, usually holding tight to the thickest snags and dead fall cover along riverbanks of the Fly or Sepik where they wait to ambush prey.

They are also found in estuaries, which is a partly-enclosed coastal body of water with one or more rivers or streams flowing into it, but is essentially open sea. The attraction to estuaries is often associated with an abundance of life, which provides a good source of prey for the Niugini Bass. Normally, estuaries are more likely to occur on submerged coasts that results when the sea level has risen in relation to the land and this process floods valleys to form rias and fjords. Of the two primary rivers systems where the Niugini Bass are found, only the Fly river has an estuary.

The fly is the second largest river in Papua New Guinea, extending for some 1,000 kilometres and is considered the largest river in terms of water flow per unit catchment area, which is due to the very high rainfall in the region. It is a relatively slow moving river due mainly to its slow drop, only a mere 65

feet/20 metres over 497 miles/800 kilometres. Much of the Fly’s catchment area consists of dense tropical rainforest. The Fly’s midsection flows through tropical swamp forest while further downstream the drier climate gives rise to open savannah forest and grasslands.

As a result of the dense forests lining the banks of the fly, it offers many submerged trees and forest-related debris where it lies in wait of its prey before striking. However, the introduction of several foreign species has caused stress for local fish like the Niugini Bass.

The climbing perch (Anabas testudineus), the walking catfish (Clarias batrachus) and the snakehead (Channa striata) were first noticed in 1990’s. Unfortunately for the Niugini Bass, these invasive species have taken off and become widespread in the system. The climbing perch has become a popular prey for the Niugini Bass, which at first sounds positive, but the spines of the fish often get caught in it’s throat and the throats of many other species. The climbing perch and walking catfish also compete with native species for both food. Another threat to the Niugini is deforestation and pollution.