The kaluga (Huso dauricus) is a large predatory sturgeon found in the Amur River basin. Also known as the river beluga, they are claimed to be the largest freshwater fish in the world, with a maximum size of at least 1,000 kg (2,205 lb) and 5.6 m (18.6 ft). The kaluga is one of the biggest of the sturgeon family. Like the slightly larger beluga, it spends part of its life in salt water. Unlike the beluga, this fish has 5 major rows of dermal scutes, nail-like teeth in its jaws, and feeds on salmon and other fish in the Amur. They have gray-green to black backs with a yellowish green-white underbelly.