Part of the high species diversity in the Kapuas is related to the many different habitats in the river basin. In the headwaters are fast-flowing highland streams, typically dominated by small loaches, and small —often acidic (blackwater)— forest streams and peat swamps with species such as the tiny Sundadanio rasboras and macropodusine gouramis.[17] The main river itself also includes several habitats, ranging from the nearshore to open waters. In the deepest sections, no light exists and in one species, Lepidocephalus spectrum, this has resulted in a complete reduction of both eyes and pigmentation (similar to cavefish).[19]