🪰 Fly Family Tree

Click a coloured box to open its branch; click a picture card for that fly. Details appear below.

Click a labeled part. Fly head (eye end) is on the left, tail on the right.

Hooks & sizes

TermMeaning
Size numberBigger number = smaller hook. #8 is big (stonefly/hopper), #14 medium (caddis/PMD), #20 small (BWO), #24 tiny (midge).
Dry-fly hookThin wire so it floats; e.g. standard-length, fine wire.
Nymph hookHeavier wire, often curved (“scud/ grub”) to sink and shape a curled body.
Streamer hookLong shank (2XL–6XL) so a long body hangs off one hook; strong wire.
Barbless / barbedPinch the barb down: easier release, less damage to fish; required on many waters.
GapThe opening between shank and point; wider gap = better hookup, narrower = more hidden.

Materials: what each does

MaterialUse
ThreadHolds everything; color shows through thin bodies; 6/0–8/0 common, 14/0+ for midges.
Hackle (rooster)Stiff fibers; floats a dry fly, kicks the legs of a dry.
Hen / partridgeSoft, pulsing fibers for soft hackles and wets.
DubbingFuzzy fur/synthetic spun on thread for a buggy body (hare’s ear, beaver, Superfine).
CDCDuck rump feathers: float and trap air; great for emergers.
Deer / elk hairHollow, buoyant; wings (Comparadun, Elk Hair Caddis) and heads.
MarabouWavy feather that breathes in water: streamer tails and wings.
Pheasant tailBrown, banded fibers: nymph tails, bodies, legs.
Wire / tinselRibbing: segments the body, adds flash and protects it.
Bead (brass/tungsten)Head and weight; tungsten is ~1.7× heavier. Colors act as a hot spot.
Lead / non-lead wireWraps on the shank for weight under the body.
FoamClosed-cell: unsinkable bodies for terrestrials and poppers.
Flash (Krystal Flash)Adds a bit of sparkle to streamers and attractors.

By insect (how shops like Fly Deal sort them)

Same insect, different life stage = different fly family.

Glossary

Plain-language meanings of fly-fishing words, parts and abbreviations. No experience needed.

How the tree is organised (read this once)

  1. Where the fly rides in the water decides the family: surface (dry), film (emerger), sub-surface (nymph/wet), anything-depth (streamer).
  2. What it copies decides the branch: a mayfly, caddis, stonefly, midge, terrestrial, crustacean, or baitfish.
  3. How it’s built decides the pattern (Parachute vs Comparadun vs Catskill are all mayfly dries, built differently).

The insect life cycle explains why one insect gives you several flies: egg → nymph/larva → (pupa for caddis/midge) → emerger → adult (dun) → spinner. Fish eat every stage, so there’s a fly for each.

InsectLife stages (and fly family for each)
MayflyNymph (nymph) → emerger (film) → dun (dry) → spinner (spent dry)
CaddisLarva (nymph) → pupa (nymph/soft hackle) → adult (dry)
StoneflyNymph crawls to bank, hatches on land; adult returns to lay eggs (dry)
MidgeLarva (nymph) → pupa (emerger) → adult (cluster dry)