Paddlefish

Their biological nature means they are obliged to swim day and night to breathe

Paddlefish live in the deep slow-moving waters in North America, the Mississippi river and its tributaries. It uses its long paddle, called a rostrum, to detect its food, mainly plankton, and direct it towards its mouth. From the Polyodontidae family, they belong to the same order as sturgeons. Extremely rare in aquariums, their biological nature means they are obliged to swim day and night to breathe.