Herrings (Clupeidae)

1. very thin, silvery body;
2. scaleless head;
3. belly with saw-toothed edge..

Carps & Minnows (Cyprinidae)

1. single dorsal fin;
2. abdominal pelvic fins;
3. thin lips.

Suckers & Redhorses (Catostomidae)

1. large, thick lips on short, broad head.

Mudminnows (Umbridae)

1. small mouth;
2. rounded caudal fin;
3. dorsal and anal fins far back on body.

Smelts (Osmeridae)

1. small, slender, silvery body;
2. teeth on jaws and tongue;
3. adipose fin;
4. no spines.

Salmons, Trouts, & Whitefishes (Salmonidae)

1. adipose fin;
2. no spines;
3. small triangular flap at base of pelvic fin.

New World Silversides (Atherinopsidae)

1. small, upturned mouth on long snout;
2. two widely-separated dorsal fins (first very small with spines);
3. long, sickle-shaped anal fin.

Topminnows (Fundulidae)

1. flattened head and back;
2. upturned mouth;
3. single dorsal fin located far back on body.

Trout-perches (Percopsidae)

1. adipose fin;
2. spines on leading edge of dorsal and anal fins.

Sticklebacks (Gasterosteidae)

1. three to nine isolated dorsal spines in front of dorsal fin;
2. extremely narrow caudal peduncle.

Sculpins (Cottidae)

1. one to four spines at rear margin of cheek;
2. large fan-like pectoral fins;
3. large head;
4. body tapering to narrow caudal peduncle.

Perches & Darters (Percidae)

1. two separate dorsal fins - first with spines, second with rays;
2. one to two spines on leading edge of small anal fin;
3. single, flat spine at rear margin of cheek.

Gobies (Gobiidae)

1. pelvic fins fused to form suction cup.

Crayfishes (Cambaridae)

Lampreys (Petromyzontidae)

1. scaleless body;
2. round, disc-like mouth without jaws;
3. no pectoral or pelvic fins;
4. seven pairs of gill openings.

Sturgeons (Acipenseridae)

1. very thin, silvery body;
2. scaleless head;
3. belly with saw-toothed edge.

Gars (Lepisosteidae)

1. long, slender, cylindrical body with diamond-shaped, armour-like scales;
2. long, slender snout with needle-like teeth;
3. dorsal and anal fins far back on body.

Bowfins (Amiidae)

1. long, spineless dorsal fin;
2. rounded caudal fin;
3. large, bony plate underneath lower jaw.

Mooneyes (Hiodontidae)

1. large eyes far forward on scaleless head;
2. forked caudal fin;
3. mouth with teeth.

Freshwater Eels (Anguillidae)

1. long, thin body;
2. long dorsal fin joined to caudal and anal fins;
3. pectoral and pelvic fins present;
4. single pair of small gill openings.

North American Catfishes (Ictaluridae)

1. four pairs of whisker-like barbels around mouth;
2. adipose fin;
3. scaleless body;
4. spines leading pectoral and dorsal fins.

Pikes and Pickerels (Esocidae)

1. duckbill-like snout;
2. dorsal and anal fins far back on long, cylindrical body;
3. large teeth.

Cods (Gadidae)

1. short barbel at tip of chin;
2. long dorsal and anal fins;
3. tiny scales.

Temperate Basses (Moronidae)

1. thin, deep body;
2. large spine on gill cover;
3. two distinct or slightly joined dorsal fins;
4. silvery body.

Sunfishes (Centrarchidae)

1. two broadly joined dorsal fins - first with spines, second with rays;
2. three to nine spines on leading edge of anal fin.

Drums (Sciaenidae)

1. two dorsal fins - first with spines but shorter than second;
2. lateral line extends to end of caudal fin;
3. deep body, highly-arched at first dorsal fin origin.