Troutnut.com: Over 4480 Aquatic Insect Pictures for Trout Fly Fishing Nuts: See over 4480 close-up photos of mayflies, stoneflies, caddisflies and other trout stream invertebrates. There are also movies, underwater photos of nymphs and larvae in their natural habitat, stream scenery, and desktop backgrounds. Learn how to identify invertebrates and how to match their behavior!