Identifying the habitat selection patterns of aquatic species is necessary for protecting threatened and endangered native fishes, as well as for producing satisfying and exciting sport fisheries. This field lesson combines fish observation with habitat data collection to evaluate fish habitat selection. The lesson can be tailored to suit undergraduate- and graduate-level students in biology or ecology programs. First, students will identify fish and document fish locations via snorkeling. Students will then collect habitat data from points used by and available to fish using the appropriate equipment. Depending on the size of the river, the number of instructors, and the amount of equipment available, this lesson is recommended for 4-20 students. Students will be asked to reflect on their observations and form a hypothesis about what habitat characteristics fish are selecting. Finally, as an optional assignment, students will use statistical models to determine important habitat characteristics based on collected or supplied data. Recommended duration for the field activity is 2 class sessions (one for Preparatory Material and one for Lab Assignment) and a 5–8-hour field lesson.