Crawfish

The Crawfish (ザリガニ, Zarigani) is a common crustacean found in the Holding Pond between the months of April to the middle of September, found at any time of the day, and it appears in the ponds. Despite its crustacean species it is classified as a fish. It is worth 250 Bells.

Donating to the Museum
Blathers makes these statements when the crawfish is donated to the museum.

In Wild World
"You'll find these little fellows in many pots across the southlands, I imagine. I've personally never sampled one. They look rather... insect-ish. Blech."

In City Folk
"...I don't do particularly well when around crawfish. I mean, really. Look at it. It's like a wretched insect! And those legs... Did you notice all those wiggly legs? All the better to revolt me. Hoo, and the vulgar belly, all segmented and buglike. Absolutely abhorrent!"

It can be found in the middle-left tank in City Folk.

In New Leaf
"These shrimp relatives are usually found in ponds and rivers, typically making them easy to catch. The reason for this strange habitat is that crawfish are plentiful and will eat just about anything. Eating plant material makes their bodies red, but only eating fish and meat will turn their bodies blue. A red color indicates they are eating a healthy and balanced diet, so red is the ideal for the species."

Encyclopedia Information
Once the player has caught a particular fish or bug, they can find information about it in the bug or fish menus. Once the crawfish has been caught, the following information can be found in the fish menu:

Further Information

 * he crawfish featured in Animal Crossing (Procambarus clarkii), is a member of one of the three largest freshwater crawfish. There are other names other than crawfish, such as crayfish, crawdads, and crawldads, known around the world in their respected territories. Crawdads are used in Louisiana's famous French Quarter as food.