The two confusions worth naming are the flatworm and the aquatic worm, and they fail in opposite directions. A flatworm has no segments and no suckers. An aquatic worm has segments and bristles but no suckers. A leech has segments and suckers and no bristles at all.UMW-AQUATIC-INVERTS, EPA-MACROINVERT-FIELD-GUIDEDispute
Note what does not help: both leeches and flatworms are flattened. Flattening on its own separates nothing.Dispute
The tell
What settles it, and what settles against it.
Read off this record's own diagnostic weights, heaviest first. A structure near the top of the left column does most of the work on its own; one near the bottom only leans.
Argues for Leech
A sucker at each end of the body+6
No hardened head capsule and no legs — soft and segmented throughout+4
Argues against it
Fish-shaped forage silhouette (minnow / shiner / fry) — not an insect-5
Bundles of fine bristles along the segments-5
A row of leg-like flaps down both sides of the body-5
Moving as a school or tight bait cluster, not as a single insect-4
Head everts a proboscis carrying dark jaws-3
A structure at −4 or below is treated as a hard exclusion by the comparison tool rather than as a penalty: if you saw it, this group is ruled out and no amount of matching elsewhere brings it back. Run a comparison →
No hardened head capsule and no legs — soft and segmented throughout
Confused with
Telling it from what it isn't.
LeechvsAquatic worms
Bristle bundles along the segments and no suckers is an aquatic worm. Suckers and no bristles is a leech. The pair is reciprocal, but the bristles are often too fine to see, so check the suckers first.
Where in the column it mattersNear the bottom. Mostly on vegetation, under stones or in bottom muck. Leeches also swim, so one can be met above the bottom.
Read from the record's own position notes: on vegetation, under stones and logs, or in bottom muck; warm calm shallow water, especially where weed is thick.
What eats it
Which fish the dossiers actually name.
No reviewed dossier names this group. That is an absence in the dossier layer rather than a finding about the animal — four dossiers exist and only one of them names any forage group at all.
The pattern layer ties this group in Streamer. That is a correspondence between an imitation and an animal, worked out when the patterns were written. Whether a fish is on it today is a question this page cannot reach.
Bunny Leech
Streamer
Hook4–10
A leech — a sucker at each end, nothing else needed.
Slow strips with long pauses. Pulsing material does the undulation.
7 of them. The limits are part of what was reviewed rather than a disclaimer bolted on afterwards. An entry that hid them would be claiming more than it checked.
Written by the reviewer
Declared by the reviewerNo source consulted states whether leeches are nocturnal or day-active beyond the observation that they usually avoid light, and none addressed seasonal activity.Dispute
Declared by the reviewerNo source consulted reports leeches in the invertebrate drift.Dispute
Declared by the reviewerThe size range is wide because leeches stretch and contract dramatically.Dispute
Declared by the reviewerThe size range is very wide because leeches stretch; treat any observed length as approximate.Dispute
Sources disagreeSucker count is worded differently. Missouri says there is a sucker at each end; EPA's Pacific Northwest guide gives front and rear suckers but says the front one may be small; the Upper Midwest guide says a suction disc is present at one or both ends.
Read off the record
Nobody typed these. They are fields that are empty, said out loud rather than left for you to notice from a section that simply is not there.
SeasonalityNo reference window is published for this group, so this entry says nothing about when it is available. That is an absence in the calendar layer, not a claim that the animal has no season.
What eats itNo reviewed species dossier names this group. Some dossiers describe forage in class terms — small forage, insects, bait — and those are shown below, but a class description is not a reviewed link to this group and none is claimed.
Sources
Everything above rests on 5 published pages.
These are every page behind this entry. Where a reviewer traced a line above to the pages that carry it, that line names them itself, with where the evidence comes from when it is narrower than the whole entry. A line with no names beside it rests on this list as a whole: nobody has yet checked which page carried it, and naming one would be a mapping nobody made.
A plate shows shape. It cannot show a gill beating, a mask firing, or an animal reversing into sand — so where motion is the field mark, the entry points at motion. These are demonstrations, selected by hand and by publisher. Nothing here is a source: it changes no score, no window and no reviewed claim.
Stroud Water Research Center. The swimming undulation and the inchworm crawl that alternately anchors each end — which is what makes 'a sucker at each end' visible.
Research institute · external video · title read back from the publisher 2026-09-09
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These send the class of animal and the water this record is documented in. They do not send a sighting, because this page does not have one — you have not told it what you saw.
Which fish in this kind of water are documented eating this class of forage, and how they behave when they are.
What this forage class asks of the setup — the weight it wants, and where the chain gives first.
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