Freshwater crayfish are crustaceans found in rivers, lakes, and streams around the world. They have a hard exoskeleton, two large pincers, and a segmented body. These creatures play a vital role in their ecosystems by helping to recycle nutrients and serving as food for various predators, including fish and birds. There are over 500 species of freshwater crayfish, with notable examples like the American Red Swamp Crayfish and the Signal Crayfish. They are typically nocturnal and feed on plants, insects, and detritus. Freshwater crayfish are also popular in aquaculture and are often harvested for culinary purposes.