Which freshwater fish uses a long, paddle-shaped snout to detect prey?

The American paddlefish uses a long, paddle-shaped snout to detect prey.

Its rostrum is covered with electroreceptors that sense the weak electrical signals produced by zooplankton and other organisms. The fish swims with its mouth open and filters tiny prey from the water using fine gill rakers.

American paddlefish live mainly in the Mississippi River basin and historically ranged through large rivers and connected lakes. They are related to sturgeons, but their paddle-shaped snout makes them immediately recognizable.

The snout is not a weapon and does not function like a conventional nose. A common mix-up is confusing paddlefish with sawfish: sawfish have toothed rostra and are marine or coastal rays, while the American paddlefish has a smooth rostrum and is a freshwater fish. Paddlefish are also valued for their roe, which is marketed as paddlefish caviar.