Dichotomous Key for Butterflyfish
Genus Chaetodo
Genus Chaetodo
Pelvic fin dark
Pelvic fin light
Go to #2
Go to #4
Two large white spots below dorsal fin
Lacks two large white spots below
C. quadrimaculatus
Go to #3
Tail with two dark bars at tip
Tail with one dark bar at tip
C. reticulatus
C. kleini
Posterior or dorsal fin has long filament extension
Filament extension lacking from dorsal fin
Go to #5
Go to #6
Large dark spot on body near filament
Small dark spot on body near filament
C. ephippium
C. aurigia
No vertical band through eye
Vertical band through eye
C. fremblii
Go to #7
Incomplete eyeband on face (does not go to top of head)
Complete eyeband on face (extends to top of head)
C. multicinctus
Go to #8
Nose area with band
Nose area lacks band
Go to #9
Go to #10
Fewer than eight diagonal bands on body
More than eight diagonal bands on body
C. ornatissimus
C. trifasciatus
Distinct white spot splits eyeband above eye
No white spot above eye; eyeband not split
C. lineolatus
Go to #11
Upper third of body under dorsal fin dark
Upper third of body under dorsal fin not dark
C. tinkeri
Go to #12
Distinct small spots arranged in rows
No distinct small spots; body has large spot or band
Go to #13
Go to #14
No black band on caudal fin
Obvious black band on caudal peduncle
C. citrinellus
C. miliaris
Side with a large black teardrop; no dark bars on tail
Large black shoulder patch; tail with dark bars
C. unimaculatus
C. lunula