7621

• UCREFRP Catalog Number: 7621
• Author: Woodling, J.
• Title: Colorado's Little Fish
• USFW Year: 1985.
• USFW - Doc Type: A Guide to the Minnows and Other Lesser Known Fishes in the State of Colorado.
• Copyright Material: NO

8. a. Head without scales
Go to Number 9.
b. Head with at least some scales on
cheeks.
Go to Number 11.
9. a. Gill opening on underside of head
(throat) extends forward to a point
beneath the eye. Lower margins of
gill covers overlap along the mid-
dle of the throat. Last ray of dor-
sal fin extended into a long
slender filament (except in very
small fish).
Family CLUPEIDAE
Herrings. See page 50.
b. Gill opening on underside of head
does not extend forward to a point
beneath the eyes. Lower margins
of gill covers do not overlap along
middle of throat. Last ray of dor-
sal fin not extended into a long
filament.
Go to Number 10.
10. a. Dorsal fin usually with 8 rays,
caudal fin normally with 19 rays,
pharyngeal arch with one or two
rows of teeth with never more than
7 teeth in a single row.
Family CYPRINIDAE (in part).
Minnows. See page 17.
b. Dorsal fin with 9-10 rays, caudal fin
normally with 18 rays, pharyngeal
arch with a single row of more
than 15 teeth.
Family CATOSTOMIDAE.
Sucker. See page 52.
11. a. Tail deeply forked. Jaws duck-like
in shape with many large sharp
teeth.
Family ESOCIDAE.
Northern Pike.
Not covered in this book.
(See Woodling 1980).
b. Tail rounded or oblong, jaws short,
normal fish shape. Teeth are small.
Go to Number 12.
12. a. Third anal ray branched, anal fin
of males and females similar.
Family CYPRINODONTIDAE.
Killifishes. See page 62.
b. Third anal ray unbranched, anal
fin of male altered into an in-
tromittant organ.
Family POECILIIDAE.
Mosquitofish.
See page 64.
13. a. Body without scales.
Family COTTIDAE.
Sculpin. See page 65.
b. Body with scales.
Go to Number 14.
14. a. Distance from rear margin of gill
cover to the forward edge of the
pelvic fin much greater than the
distance from the forward edge the
pelvic fin to forward edge of the
anal fin.
Family ATHERINIDAE
Silversides.
Not covered in this book. Brook
silversides have been stocked in
Colorado, but there are no known,
existing populations.
b. Distance from the rear margin of
gill cover to the forward edge of
the pelvic fin much less than
distance from front edge of pelvic
fin to front edge of anal fin.
Go to Number 15.
15. a. Anal fin with three spines.
Go to Number 16.
b. Anal fin with one or two spines.
Go to Number 17.
16. a. Spiny dorsal fin and soft dorsal fin
well separated. Sharp spine at rear
edge of operculum (gill cover).
Family PERCICHTHYIDAE.
White bass, Wiper. Not covered in
this book.
(See Woodling 1980).
b. Spiny and soft dorsal fin con-
nected. No spine at rear edge of
operculum.
Family CENTRARCHIDAE.
Sunfish and Bass not covered in
this book.
(See Woodling 1980).
17. a. Lateral line does not extend into
anal fin. Soft dorsal fin (less than
23 rays) is not longer than spiny
dorsal fin.
Family PERCIDAE.
Perch. See page 67.
b. Lateral line extends well into tail.
Soft dorsal (more than 23 rays) is
longer than spiny dorsal.
Family SCIAENIDAE.
Freshwater drum. Not covered in
this book.
(See Beckman 1952).
Colorado's Little Fish 12