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Hatch MatchHook the Horizon · field intelligence

Where motion is the field mark

Some of this only exists in time.

A plate shows shape. It cannot show a gill beating, a mask firing, or a mole crab reversing into the swash — and for a good number of these groups, that is the whole identification.

How this list is built

52 demonstrations · 34 of 39 groups · 5 declared gaps

Motion has to earn the row. A video is here because it shows movement, a life-stage transition, or a structure handled on camera — not because it covers the same animal. A slideshow of the stills this guide already carries adds nothing, and a fly-tying tutorial is an argument about imitation rather than a look at the animal.

Selection runs on publisher first and reach second, which is why a research institute's forty-view clip of a sowbug outranks anything with a million plays. Where the topic is a method rather than an animal — working a kick-net, reading a seam — an angling educator is the right publisher and is used as one.

Nothing here is evidence. No video changes a score, a seasonal window, or a reviewed claim. The reference set cites named agencies and peer-reviewed work, and that stays the only thing this application will stand behind. Every title and channel below is the string the publisher returns for that link; npm run watch:verify reads all of them back and fails on a drift, a deletion, or a group that has quietly acquired neither a video nor a stated reason for having none.

Before the comparison has anything to compare

Getting a look at one, and reading the water it came out of.

Getting a look at one

The comparison needs a structure you actually saw. Most of the time that means turning a rock or working a net, and doing it in the order that leaves the animal intact.

How it moves once it lets go

A reference window says an animal is plausible. It says nothing about what it does in current — and what it does in current is most of why it matters.

  • "Bugs of the Underworld" - Stoneflies ↗

    In-stream footage of nymphs crawling, releasing and tumbling. This is drift, filmed, rather than drift described.

    MIDCURRENT · Specialist angling channel · read back 2026-09-09

Reading the water it came out of

Water type is the one context field that eliminates records outright in this instrument. Knowing a riffle from a run from a pool is what makes that answer honest.

By group

The structures, moving.

Mayfly

Stonefly

  • STONEFLY life cycle and other things you should know ↗

    Why a stonefly crawls out to emerge instead of hatching midstream — the behaviour behind this entry's emergence note.

    Huge Fly Fisherman · Specialist angling channel · read back 2026-09-09

  • Stoneflies in Motion ↗

    A nymph doing push-ups to drive water over its thoracic gills. Gill position separates this group from a mayfly; the push-up is how you notice it.

    Leaf Pack Network · Research institute · read back 2026-09-09

  • Winter stonefly, nymph and adult 2021 ↗

    Nymph and winged adult in the same field, in the season most anglers assume nothing is out.

    Bug of the Week · Science media · read back 2026-09-09

Hellgrammite

Baitfish / forage silhouette

Shad (gizzard and threadfin)

Cisco / lake herring

No video. Credible material is conference talks and restoration webinars with no footage of the fish; everything showing a cisco is an ice-fishing catch video.

Crayfish

  • Crayfish in Motion ↗

    Walking forward on its legs, then the backward tail-flick retreat. Two locomotion modes, one of them this entry's cue.

    Leaf Pack Network · Research institute · read back 2026-09-09

Leech

  • Leech in Motion ↗

    The swimming undulation and the inchworm crawl that alternately anchors each end — which is what makes 'a sucker at each end' visible.

    Stroud Water Research Center · Research institute · read back 2026-09-09

Aquatic worms

No video. No agency, museum or extension footage of Tubificidae in motion. The space is stock-footage listings and aquarium fish-food content, and a microscope clip of a different family would teach the wrong animal.

Silversides

No video. Stock-footage agencies and bait-catching vlogs only. Nothing from a biologist, agency, aquarium or museum showing Menidia schooling.

Anchovies

  • Anchovies in the Kelp Forest Exhibit ↗

    A polarised school flashing and turning, with the oversized eye catching light — the cue that separates an anchovy from a silverside at distance.

    Monterey Bay Aquarium · Museum or aquarium · read back 2026-09-09

Killifish (mummichog and striped killifish)

  • Ask an Expert: What Are Mummichogs (And Why Are They Amazing)? ↗

    The live animal talked through: the blunt head and small upturned mouth, in the marsh context they belong to.

    Chesapeake Bay Foundation · Public agency or non-profit · read back 2026-09-09

  • Mummichogs ↗

    Surface-oriented, tidepool-hugging movement — which separates a killifish from a shiner at a glance and has nothing to do with shape.

    seacoastsciencectr · Museum or aquarium · read back 2026-09-09

Shrimp (grass and penaeid)

No video. The available tail-flick and rostrum clips are unattributed uploads or aquarium-hobby content. The well-made shrimp films are mantis and snapping shrimp — a different body plan, on a page about telling body plans apart.

Blue crab (young)

  • Blue Crab 101 ↗

    Live crabs handled on camera with the paddle rear legs and the lateral spines pointed out on the animal.

    Chesapeake Bay Foundation · Public agency or non-profit · read back 2026-09-09

Marine worms

  • BLOODWORMS - Will They BITE?! ↗

    A bloodworm everting its proboscis and firing the four dark jaws, in close-up. This entry's defining cue, and the reason to hold one carefully.

    Brave Wilderness · Science media · read back 2026-09-09

Cranefly larvae

  • Crane Flies in Motion ↗

    The peristaltic, headless-looking crawl and the fleshy rear lobes flexing — why 'leatherjacket' describes a way of moving.

    Leaf Pack Network · Research institute · read back 2026-09-09

Freshwater snail

  • Aquatic Snails in Motion ↗

    A snail gliding on an extended muscular foot with the shell trailing, which is how you tell one from a cased caddis in a tray.

    Leaf Pack Network · Research institute · read back 2026-09-09

Alderfly larva

No video. The obvious candidates are Corydalidae, which is the hellgrammite. Pointing a Sialidae entry at a dobsonfly larva would put the wrong animal on the page that exists to separate them.

Black fly larva

  • Black Fly in Motion ↗

    Anchored by the swollen rear while the body sweeps in the flow. Posture plus motion is the whole signature of this larva.

    Leaf Pack Network · Research institute · read back 2026-09-09

The five with nothing

A short honest library beats a complete invented one.

Cisco, aquatic worms, silversides, shrimp and the alderfly larva have no link, and each one says why on its own entry. Four of the five are small silver fish or small pale invertebrates, which is not a coincidence — the animals hardest to tell apart are the ones nobody makes films about, and that is precisely where a film would help most.

If you know of something for one of them from a publisher that would survive the rule above, the correction form takes it.