Macro view of a cold stream surface film at dawn with a nymph silhouette suspended below the meniscus

Biology before bravado

What did you actually see?

Compare visible cues against a small reviewed reference set. Broad context helps; exact coordinates do not belong here.

Surface film, first light — the moment most identifications are actually made.

Hypothesis boundaryReference plausibility is not a current observation. Check conditions, regulations, access, safety and conservation guidance separately. After comparing at least one visible cue you can share your observations with Field Ops.

39 reviewed groups · reviewed 2026-09-04Next review 2026-12-03

Observe first. Name later.

01Visible cues

Required — select every structure you actually saw.

Tails & body

Wings & gills

Summer & forage

Fish structure

Crustaceans & worms

Salt-water forage

Squid & octopus

Shells

Try this

Live

Nothing selected. The instrument stays silent rather than guessing — pick a structure above and this updates as you go.

Water typeObserved life stageApproximate size band

I don’t know what I sawnarrow it down instead

This does not identify anything. It takes what you can honestly say and shortens the list, then tells you which single structure would do the most work if you went back and looked.

What kind of animalThe easiest question here, and the one that removes the most.Where in the waterDepth narrows but never excludes — anything can be dislodged.How it movedMatched against how each group's movement is described in the reference set.

Water type, life stage and size carry down from the form above; add any of them and the list will shorten.

Still open 39

Mayfly
Caddisfly
Stonefly
Midge (non-biting)
Hellgrammite (dobsonfly larva)
Scud / Amphipod (crustacean lookalike)
Terrestrials (ants, beetles, hoppers)
Baitfish / forage silhouette
Damselfly / Dragonfly (Odonata)
Aquatic beetles (Coleoptera)
Shad (gizzard and threadfin)
Alewife / river herring
Cisco / lake herring
Shiners and minnows
Yellow perch, young-of-year
Sunfish, young-of-year (bluegill and kin)
Crayfish
Leech
Aquatic worms
Sand lance (sand eel)
Silversides
Anchovies
Menhaden (bunker, pogy)
Shrimp (grass and penaeid)
Mole crab (sand flea)
Blue crab (young)
Marine worms (clam worm, sandworm, bloodworm)
Inshore squid
Mullet (young)
Killifish (mummichog and striped killifish)
Sculpin
Water boatmen
Backswimmers
Cranefly larvae
Aquatic sowbug (aquatic isopod)
Freshwater snail
Clam (small freshwater bivalve)
Alderfly larva
Black fly larva

Go and look at one of these

Each of these structures divides what is still open — some groups have it, others cannot. Confirming one is worth more than any amount of further guessing.

Fish-shaped forage silhouette (minnow / shiner / fry) — not an insectSeparates 14 groups from the rest of what is open.
Moving as a school or tight bait cluster, not as a single insectSeparates 14 groups from the rest of what is open.
Wings held flat and parallel along the bodySeparates 6 groups from the rest of what is open.
Hardened head with softer worm-like abdomenSeparates 6 groups from the rest of what is open.

Select at least one visible cue in step 01. Context in step 02 is optional. The comparison will not invent a match. Next: pick a cue, or run Mayfly nymph. Start Here