Here's a great field study or service learning project for biology students. Check with your local fly fishing clubs or the Federation of Fly Fishers, and see if there is a local equivalent to California's Trout in the Classroom program. Students receive the aquarium and chillers from the local fly fishing club; the State Dept. of Fish and Game provides the eggs. Trout are raised and studied until they are big enough to be released in a local stream designated by Fish and Game. We've done it at my high school for several years and the kids love it.