Crayfish, also known as "crawfish" or "crawdads," are easy to keep in the classroom, and with patience and luck, students will observe the complete life cycle of the crayfish. They will also learn about aquatic animals and habitats and get to conduct inquiry experiments about animal behavior. This article describes how a third-grade teacher used crayfish to teach her students about aquatic habitats, animal adaptations, and life cycles through observations and inquiries. (Contains 2 figures, 4 resources and 3 online resources.)