Arut

Betta uberis is a small bubble-nesting labyrinth fish from peat swamp forests in Central and West Kalimantan, Borneo, Indonesia. Most records come from between the lower Arut and Kumai rivers near Pangkalan Bun. Known to aquarists as Betta sp. 'Sukadana' or B. sp. 'Pangkalanbun' before its description, it belongs to the B. coccina group and is named for its high count of 14 to 17 dorsal-fin rays, which also separates it from its nearest neighbour in the group, B. hendra.

Parosphromenus opallios is a liquorice gourami endemic to Central Kalimantan province in Indonesian Borneo, in the Arut and Benipah river systems. It appeared in the trade on a handful of occasions as P. sp. 'Sukamara' before its description, and occurs alongside P. linkei at Sukamara. A stenotypic inhabitant of peat swamp forests and blackwater streams, it appears in danger of extinction.