A smooth-coated otter is characterized by a very smooth, sleek pelage. Their eyes and ears are small, the tail is attened, limbs are short, strong, and the fore and hind paws are large and well-webbed. These otters have generally been described as fish specialists. They are strong swimmers and hunt in groups. When fishing they travel in a V-formation going upstream. Most foraging activity occurs in water and small fish are swallowed whole, but large fish are taken to shore. Males are polygamous, mating with up to four females.

The females often dig their own breeding dens and maintain small family groups of a mated pair with up to four offspring.