First checkSegmented, round, no legs, no hard head — then look for bristle bundles and check both ends for suckers.
A soft segmented tube, round in cross section, with no legs and no hardened head. Bundles of fine bristles run along the segments and are the character that separates it from a leech.
Where you find them is more interesting than what they look like. Tubificids anchor head-down in the sediment with the rest of the body extending up into the water and waving there. They are in the substrate without being out of reach.
One warning about a common shortcut: looking for a hard head capsule separates a worm from a midge larva, which has one, but not from a cranefly larva, whose head is concealed under the skin. Use the cranefly's fleshy hind lobes instead.
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 Aquatic worms
Bundles of fine bristles along the segments+5
No hardened head capsule and no legs — soft and segmented throughout+5
Argues against it
Fish-shaped forage silhouette (minnow / shiner / fry) — not an insect-5
A sucker at each end 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-4
A row of leg-like flaps down both sides of the body-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 →
Life stages
What it looks like, stage by stage.
Aquatic worms — Adultdrawn
Adult
Size in hand1–150 mm across the group; tubificids to about 25 mm
What you see
Many segments, round in cross section, no legs, no hardened head
Bundles of fine bristles on most segments
Colour from white through red and tan to brown or black
Blunt at both ends with few other features
Where it turns up
Soft sediment and silt in quiet water; head buried in a tube with the body extending upward.
How it moves
Stretching and pulling like an earthworm; waving while anchored in the sediment.
Cues this stage offers the comparison
Bundles of fine bristles along the segments
No hardened head capsule and no legs — soft and segmented throughout
Confused with
Telling it from what it isn't.
Aquatic wormsvsLeech
A sucker at each end is a leech. Bristles and no suckers is a worm.
These groups name Aquatic worms in their own separators. If you arrived holding one of them and were not sure, this is the sentence that pointed you over.
Crayfishsaid
If it has no legs and no hard parts at all, it is a worm. A crayfish is armoured throughout.
No head, thorax or abdomen distinction at all, with bristle bundles along the whole body, is an aquatic worm. A cranefly larva has a head capsule, even a withdrawn one, and a distinct lobed tail disc.
Where in the column it mattersIn the substrate. Anchored head-down in a tube in the sediment with the rest of the body extending up and waving in the water. In the substrate, but not entirely out of reach.
Read from the record's own position notes: in soft sediment and silt; head buried in a tube in the bottom with the rest of the body extending upward into the water; quiet water with decaying organic material.
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.
Nothing in the pattern layer is mapped to this group, so no presentation family follows from it here.
Not known
What this entry cannot tell you.
8 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 reviewerThe upper size figure is uncertain: two readings of the same regional guide returned different mid-range values. Treat 1–150 mm as a wide envelope, not a measurement.
Declared by the reviewerNo source consulted describes aquatic worms generally as free-swimming; one naidid species is recorded swimming with a wriggling motion.
Declared by the reviewerNo source consulted reports oligochaetes in the invertebrate drift, and none was found describing terrestrial earthworms washing into streams and being eaten there.
Declared by the reviewerThe upper size figure is uncertain: two readings of the same regional guide returned different mid-range values. Treat 1 to 150 mm as a wide envelope rather than a measurement.
Declared by the reviewerNo source consulted describes aquatic worms generally as free-swimming in the water column; one naidid species is recorded swimming with a wriggling motion.
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.
PatternsNo fly pattern in the pattern layer is mapped to this group. Whether anything imitates it is not answered here.
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 3 published pages.
Attribution here is to the whole record, not to individual sentences — the carrier attaches a source set to a record and does not say which page carried which line. Naming one per claim would mean inventing a mapping nobody reviewed.
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.
Declared gap. 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.
Carry it on
Take the group to the next step.
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.
Keep the group on the day's record, so a later entry can be compared against what you were looking at.
Found an error?
This entry was written and drawn away from your water. If something here is wrong, say so — the report is assembled in your browser and sent only if you send it.