First checkTwo separate dorsal fins with a gap between them, and bars rather than a stripe. That is a young perch.
The spiny-rayed cut is the most useful single division in freshwater forage. Minnows and herrings have one soft dorsal fin and no spines. Perch and sunfish have a spiny fin at the front. Everything else follows from that.
A young perch shows two dorsal fins with a clear gap between them, six or seven broad dark bars running down a brassy flank, and spines on the tip of the gill cover.
It also changes address during its first season. Near-shore pelagic schools for the first thirty to forty days, then a move to the bottom. Where you meet one depends on how old it is.
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 Yellow perch, young of year
Fish-shaped forage silhouette (minnow / shiner / fry) — not an insect+6
Spiny front dorsal fin, separate from or joined to a soft second dorsal (perch, sunfish)+6
Dark vertical bars down the flank, not a horizontal stripe+5
Moving as a school or tight bait cluster, not as a single insect+4
Two dorsal fins with a clear gap between them+4
Deep-bodied and strongly flattened side to side+1
Argues against it
One soft dorsal fin only, with no spines (minnows, shads, herrings)-5
No pelvic fins on the underside at all-5
Sawtooth belly — a row of sharp scutes along the midline you can feel-4
Small fleshy fin between the dorsal fin and the tail-4
Last dorsal ray drawn out into a long trailing thread-4
Body long and thin, many times longer than it is deep-4
One dorsal fin running most of the length of the back-4
Rows of smaller spots trailing behind the shoulder spot-4
Head wide and flattened, wider than the body behind it-4
Sits on the bottom and darts — it does not hover-4
Dives into clean sand and disappears-4
Dark opercular flap (ear flap) at the rear corner of the gill cover-3
Blunt, flattened head with a small mouth at the front-3
Tail fin rounded or squared off, not forked-3
Big fan-shaped side fins the fish props itself on-3
Dark spot just behind the upper edge of the gill cover-2
Body translucent — light passes through it, and the backbone or gut shows-2
Snout overhangs the mouth, its tip in front of the jaw-2
Rounded, cigar-shaped body — not slab-sided-1
Eye diameter greater than the length of the snout-1
Mouth angled upward, the lower jaw leading-1
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.
Yellow perch, young of year — Young of yeardrawn
Young of yearthe stage a fish meets
Size in hand4–7 mm at hatching; roughly 60–80 mm by late summer
What you see
Two dorsal fins that do not join — front spiny, rear soft
Six or seven broad dark vertical bars, not a horizontal stripe
Two spines at the front of the anal fin
Spines on the tip of the gill cover
Where it turns up
Near-shore pelagic schools early, then littoral bottom. Adults hold farther out than the young.
How it moves
Schools sorted by size and age; feeds in daylight, inactive at night.
Cues this stage offers the comparison
Fish-shaped forage silhouette (minnow / shiner / fry) — not an insect
Spiny front dorsal fin, separate from or joined to a soft second dorsal (perch, sunfish)
Dark vertical bars down the flank, not a horizontal stripe
Moving as a school or tight bait cluster, not as a single insect
Confused with
Telling it from what it isn't.
Yellow perch, young of yearvsSunfish, young of year
A dark ear flap at the corner of the gill cover, and a much deeper rounder body, is a young sunfish. Perch has neither, and has gill-cover spines that sunfish lack.
Where in the column it mattersNear the bottom. The one group here that changes column during its first season: near-shore pelagic schools for the first thirty to forty days, then a shift to the bottom. Where you meet a young perch depends on how old it is.
Read from the record's own position notes: near-shore pelagic schools for the first 30 to 40 days after hatching; then a shift to the bottom as littoral bottom dwellers; schools of young fish stay near shore while adults are farther out.
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.
9 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 reviewerAgency trawl surveys put age-0 yellow perch at roughly 60–80 mm total length by late summer and autumn. Earlier in the season they are far smaller.
Declared by the reviewerNo source consulted gave a school size specific to young-of-year perch — only 50 to 200 fish for perch schools generally.
Declared by the reviewerThe separation from a young sunfish is assembled from family characters. No source consulted made that comparison directly.
Declared by the reviewerAgency trawl surveys put age-0 yellow perch at roughly 60 to 80 mm total length by late summer and autumn; earlier in the season they are much smaller, hatching at 4 to 7 mm.
Declared by the reviewerNo source consulted gave a school size specific to young-of-year perch, only 50 to 200 fish for perch schools in general.
Declared by the reviewerSeparating a young-of-year perch from a young sunfish is assembled here from family characters; no source consulted made the comparison directly.
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 6 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.
Engbretson Underwater Photography. Unedited underwater footage: the spiny front dorsal raising, and the vertical bars breaking up against cover.
Working biologist · external video · title read back from the publisher 2026-09-09
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?
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