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 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:

 

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

Mayfly Dunn

Pattern Name Color Hook Size Thumbnail Image
Pale Morning Dun - No Hackle Yellow Body # 18
Pale Morning Dun - No Hackle

Mayfly Spinner

Pattern Name Color Hook Size Thumbnail Image
Poly Wing Mayfly Spinner Black Body # 20
Poly Wing Mayfly Spinner
Trico Spinner Olive Abdomen / Brown Thorax # 20
Trico Spinner

Photo of October Caddisfly by P. Michael Carl © The Ecological Angler