A freshwater crustacean is a type of aquatic animal that lives in fresh water habitats. Two examples of freshwater crustaceans are crawdads and isopods. Crawdads, also known as crayfish, are small, freshwater crustaceans with seven letters in their name. Isopods are another type of freshwater crustacean, which have six letters in their name. They are typically small, segmented animals that live in the water.