This is the moment an adorable otter is so busy with catching fish in a river that it fails to notice it is being filmed.

The enthusiastic otter can be seen diving underwater and going back several times in the rushing stream, fussily trying to grab something.

The clip was recorded in the Land of the Leopard National Park in Primorsky Krai, Russia on June 14.

National Park representatives said in a statement 'The otter was so busy catching something tasty in the river that didn't notice the hidden filming.

'In the 'Land of the Leopard' otters feel like fish in water. By the way, they eat fish.

'Usually, hunting takes the animal 1-1.5 hours, after which the animal has to get out onto land to clean its fur.

'However, the animal's diet is not limited to fish 'dishes'

'They are not averse to eating crustaceans, amphibians, small rodents and birds, and they do not refuse plant foods.'