What Is the Difference Between a Paddlefish & a Shovelbill Catfish?

Paddlefishes

• The American and Chinese paddlefish are surviving members of a family of freshwater fish that first appeared on the scene 300 to 400 million years ago, predating the dinosaurs. As of 2011, the Chinese paddlefish of the Yangtze River system is so imperiled and rarely seen that some scientists believe it may be extinct due to severe habitat modifications, pollution and other human impacts. American paddlefish are also much reduced in number, but holding on in the Mississippi, Missouri and Ohio drainages.

The American Paddlefish

• Its huge snout, massive jaws and heavy gills are among the defining characteristics of the American paddlefish, as well as a generally shark-like build. Despite the superficial similarity, they are not related to sharks, though like those predatory fish, their bodies are mainly comprised of cartilage. Like catfish, they sport relatively smooth skin. These exotic-looking creatures are among the continent's biggest freshwater fish: huge specimens may be 7 feet long and weigh 200 pounds. Chinese paddlefish may get even larger, possibly exceeding 20 feet in length.

Ecology

• Paddlefish favor large, slow-moving rivers, backwaters, bayous and oxbow lakes, sometimes traveling thousands of miles within a large drainage network. Naturalists initially believed paddlefish used their namesake rostrums to rummage for food in muck and vegetation, but in reality they are filter-feeders. They cruise the murky depths slowly with their mouth agape, using special filaments on their gills to passively strain out zooplankton from the water rushing through. The U.S. Geological Survey reports that electrosensory receptors on the fish's snout may help it locate zooplankton clouds in the water column.

Shovelnose Catfish

• There are true catfish with names similar to "shovelbill," and thus possibly confused with unrelated paddlefish. A number of South American species are called shovelnose, including the tiger shovelnose catfish marketed in the aquarium trade and the large porthole shovelnose catfish of such wild wetlands as the Pantanal in Brazil, Paraguay and Bolivia. Despite the similarity of their common name, which stems from their flattened heads and jaws, these catfish don't much resemble paddlefish -- indeed, few fish really do.