You may know about the Asian carp, but would you know one if you saw one?

How to Identify Bighead, Silver, Grass, and Common Carp, a new video from the U.S. Fish and Wildlife Service, should change that.

The video distinguishes bighead, silver and grass carp (aka Asian carp) from their not-so-notorious brethren, common carp.

Here’s a few of the things you’ll learn:

• Silver and bighead carp have relatively large heads compared to their bodies. Their eyes sit low on the face, and their mouths slant down into a frown.

• Grass carp have narrow heads and petite mouths, and their coloring makes them look cross-hatched.

• Common carp have whiskers on their upper lip.

The U.S. Fish and Wildlife Service frequently receives calls from people who think they may have found an Asian carp, said Katie Steiger-Meister, a public affairs specialist with that agency.

Before the video, the agency’s only response was to direct people to call their state’s Department of Natural Resources.

“We are a federal agency so we can’t help people in state waters,” Steiger-Meister said. She put the video together so that the agency could offer callers something more.

The video was filmed at the Middle Mississippi Wildlife Refuge in Illinois and used live fish.

The grass carp came from an aquaculture pond in Illinois; the other fish were caught that day out of the Mississippi River.

The video is posted on the U.S. Fish and Wildlife Service’s Midwest region Facebook page and on YouTube.