Key to New Brunswick Fishes

1a Mouth without true jaws, instead a circular, suctorial disc; no paired fins; 7 pairs of gill openings.


Lampreys, family Petromyzontidae
1b Mouth with true jaws (i.e., upper and lower jaws present); with paired fins; opercles (or gill covers) overlying gills
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2a Upper and lower lobe of caudal (tail) fin, when present, of about equal size; body covering of overlapping scales or naked; no barbels before mouth; skeleton bony
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2b Upper lobe of caudal (tail) fin distinctly larger than  lower lobe; mouth inferior; snout well developed; 5 rows of bony plates arranged longitudinally along body; 2 pairs of barbels before mouth

Sturgeons, family Acipenseridae
3a Pelvic fins present


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3b Pelvic fins absent; body cylindrical, long, and snakelike; dorsal, caudal, and anal fins continuous; no distinct caudal fin.
Eels, family Anguillidae
4a Adipose fin present


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4b Adipose fin absent
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5a Body scaleless; strong pectoral and dorsal spines; long barbels about mouth.
Catfishes, family Ictaluridae
5b Body scaled; no strong spines in fins; no long barbels about mouth.
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6a Pelvic axillary process absent
Smelts, family Osmeridae
6b Pelvic axillary process present


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7a Mouth usually large, extending to middle of eye or beyond; teeth strong
Salmons and Trouts (Salmoninae), family Salmonidae
7b Mouth usually small and not extending beyond middle of eye; teeth weak or absent
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8 Dorsal fin shorter than head, dorsal rays 16 or fewer
Whitefishes, Ciscoes (Coregoninae), family Salmonidae
9a Soft (or second) dorsal fin preceded by 2-10 isolated, sharp spines or by a separate spiny dorsal of 4 slender and soft, inconspicuous spines; small fishes, less than 6 inches long; strong pelvic spines present; first dorsal spine arising well in advance of anal fin origin.


Sticklebacks, family Gasterosteidae

9b Soft (or second) dorsal fin not preceded by isolated spines, but spines, if present, joined together by fin membrane; small and large fishes.


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10a Pelvic fins abdominal and well developed; one rayed dorsal fin; all fines soft rayed and without spines.


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10b Pelvic fins thoracic or jugular, often reduced; dorsal fin usually 2, but if only 1, the anterior portion composed of well-developed spines.


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11a Gill membranes not attached to isthmus (gill openings wide)


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11b Gill membranes broadly joined to isthmus (gill openings narrow)
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12a Head with some scales; body elongate; spotted, barred, or dark coloured
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12b Head without scales; body laterally compressed; silvery; lateral line absent; teeth absent; belly with sharp, pointed scales (scutes); dorsal fin situated over pelvic fins and well in advance of anal fin; never more than 23 anal rays.
Herrings, family Clupeidae
13a Upper jaw protractile


Killifishes, family Cyprinodontidae
13b Upper jaw not protractile
Pikes, family Esocidae
14a Lips usually thick and mouth inferior (except Ictiobus where it is oblique and with normal lips; however, in Ictiobus the long dorsal fin has over 28 rays, and the longest unbranched ray is not a serrate, heavy spine, thus separating it from the 2 cyprinids with long dorsal rays, Cyprinus and Carassius); pharyngeal teeth numerous and in 1 row, comblike; swim bladder of 2 or 3 chambers.
Suckers, family Catostomidae
14b Lips thin, mouth seldom inferior (except in Rhinichthys where scales are minute and much smaller than in suckers); if dorsal fin long, no more than 22 rays and second unbranched element a heavy, serrate spine; pharyngeal teeth in 2 or 3 rows, fewer than 9 per side; swim bladder of 2 chambers.
Minnows, family Cyprinidae
15a Body plated, naked, or with prickles; pectoral fins large and conspicuous

Sculpins, family Cottidae
15b Body scaled (scales small and somewhat embedded in Gadidae); pectoral fins of moderate size, not conspicuous.
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16a Chin with small but distinct median barbel
Cods, family Gadidae
16b Chin without small median barbel
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17a Anal spines 1 or 2
Perches, family Percidae
17b Anal spines 3 or more
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18a Opercle with a spine; 3 anal spines; hemibranch well developed and obvious.


Temperate Basses, family Percichthyidae
8b Opercle without a spine; 3 or more anal spines; hemibranch concealed or absent.
Sunfishes, family Centrarchidae