The researchers studied the fish in the upper Mahakam’s tributaries in East Kalimantan to understand their diversity, potential, and conservation status. They found 26 different fish species, with Cyprinidae being the most common family. The diversity of fish varied between the different tributaries, with Maraseh River having the highest diversity. Some fish are edible, while others have potential as ornamental fish. Six species are considered of least concern, two have insufficient data, one is near threatened, one is endangered, and 16 are not on the conservation list.