What Fish Eat

Aquatic insects make up the majority of a fish's diet. The four key insect orders (listed first and not including Streamers or Terrestrials) that emerge from streams and lakes are:

Mayflies Caddisflies Midges Stoneflies Streamers Terrestrials

Mayflies Important to Fly Fishing

When fly fishing in the Western U.S., the angler can typically rely on three species to pattern mayflies. These commonly used mayfly patterns are:

Blue Wing Olive Pale Morning Dun Trico

Mayflies - Order Ephemeroptera

Mayflies are diverse with 21 families and 676 species in North America. Mayfly larvae when plentiful, can produce the bulk of a freshwater trout's diet (i.e., the role rabbits and mice play in a terrestrial ecosystems.) For identification purposes, mayfly nymphs can be divided into swimmers, clingers, crawlers, and burrowers. Swimmers are long, slender, and as their namesake suggests - great swimmers. Clingers have stouter legs, a flattened body, and a head the is narrower than the rest of the body. Crawlers are squat to the ground and their head is wider than the body.

Mayfly dun

Mayfly Nymphs

Pattern Name	Color	Hook Size
A. P. Nymph	Black Body	# 12
Copper John	Red Wire Body	# 18
Hart's Bead Head Dark Lord	Black Body (Gold Ribbing)	# 16
Flash Back Hare's Ear Nymph	Tan Body	# 16
Hare's Ear Nymph	Tan, Brown Body	# 16
Micro Mayfly	Brown Body	# 20
Montana Prince Nymph	White, Brown Wire Body	# 16
Pheasant Tail Nymph	Green Body	# 20
Bead Head Prince Nymph	Green Body	# 18
Prince Nymph	Purple Body	# 18