Rainbow Darter
  • Side view adult.
  • Side view adult.
  • Side view adult.
  • Top view adult.
  • Bottom view adult.
  • Head-on view of a breeding male.
  • Close-up flank.
  • Close-up head.
  • Bottom view of mouth and snout.
  • Close-up tail of a breeding male.
  • Close-up dorsal fin.
  • Close-up anal fin.
  • Close-up pectoral fin.
  • Close-up pelvic fin of a breeding male.
  • The side have 8-13 blotches/bars which are absent on the belly but encircling the peduncle; there are 37-49 lateral line scales (20-34 pored).
  • Close-up head: The mouth is terminal, a frenum is present, the cheeks are unscaled; there are usually 13 pectoral rays.
  • Close-up dorsal fin: The 1st dorsal lobe has 8-13 spines, the 2nd lobe has 10-15 rays, there is a slight gap between the lobes.
  • The sides of this male have 8-13 blue vertical bars with red in between.
  • Close-up anal fin: The anal fin of this male has 2 spines and 6-8 rays; it is mainly blue with orange at the base.
  • Bottom view of a male: Males have narrowly attached opercles, an orangish throat, and normal-sized pelvic fins.
  • Bottom view of a breeding male: Notice the orange throat.
  • Side view of a breeding male: Males have blue vertical bars interspersed with red, a blue and orange anal fin, and an orange throat.
  • Close-up head area of a breeding male: Breeding males show an orangish throat and unscaled cheeks.
  • Side view of a breeding male: Males have blue vertical bars interspersed with red, a blue and orange anal fin, and an orange throat.
  • Close-up anal fin of a breeding male: The anal fin is bluish with orange at the base.
  • Side view of a breeding male: Males have blue vertical bars interspersed with red, a blue and orange anal fin, and an orange throat.
  • Side view of a breeding male: Males have blue vertical bars interspersed with red, a blue and orange anal fin, and an orange throat.
  • Close-up dorsal fin of a breeding male: The dorsal fin is orange/red at its base, and dark to medium blue over the remaining portion.
  • Alternative top view.
  • Alternative view of head.
DescriptionSimilar Species
Family
Perches (Percidae)
Body
Mouth and snout: Mouth terminal, horizontal to slightly oblique, small teeth on jaws. No barbels. Body patterning, color, and scales: Back olive or brown with 3-11 dark saddles or blotches. Sides mottled, usually also with 8-13 dark regular vertical bars. Belly cream. First dorsal, second dorsal, and caudal with dark bands, other fins clear or with spotting. 37-49 ctenoid lateral scales. Body shape and size: Body fusiform to cylindrical and slightly elongated; round to oval in cross section. Typically 35-65 mm (1.5-2.5 in) TL; maximum about 75 mm (3 in).
Fins
Tail, dorsal and other fins: Rounded or square tail. Dorsal fin with 2 lobes, slightly connected or separated, the first with 8-13 (usually 10) spines and the second with 10-15 (usually 12) rays. Pelvic fins thoracic. Adipose fin absent. Anal fin with 2 spines and 6-9 (usually 7) rays.
Distinguishing Characteristics
The rainbow darter can be distinguished by its color pattern and its lack of a modified scales between the pelvic fins. See also similar species information.
Breeding Adults
Males with dark blue or greenish-blue vertical bars with orange-red pigment in-between them (most pronounced on caudal peduncle). Head mainly dark blue but sometimes yellowish red anteriorly, throat blue-black. Belly orange-red. First dorsal with orange-red base than dark blue over rest of fin; 2nd dorsal and caudal with dark blue base, then orange-red band, then blue at margin; similar but less pronounced pattern on second dorsal and caudal fin. Anal fin with orangish-red at base, rest blue. Pelvic blue, pectorals yellow-red (photos).
Juveniles
Similar to adults.
Hybrids
None known from Wisconsin.
Compare Similar Species
Dorsal Spine/Rays
Darter, Banded10-12/11-12
Darter, Fantail7-8/13-14
Darter, Iowa8-12/10-12
Darter, Least5-7/9/10
Darter, Mud10-12/10-14
Darter, Orangethroat8-12/11-15
Darter, Rainbow8-13/10-15
Anal Rays
Darter, Banded7-10
Darter, Fantail7-8
Darter, Iowa7-9
Darter, Least5-6
Darter, Mud8-9
Darter, Orangethroat4-8
Darter, Rainbow6-8
Lateral Scales
Darter, Banded41-53, all pored
Darter, Fantail41-53, 27-35 pored
Darter, Iowa55-65, 18-28 pored
Darter, Least32-38, 0-7 pored
Darter, Mud45-50, 25-43 pored
Darter, Orangethroat42-50, 10-38 pored
Darter, Rainbow37-49, 20-34 pored
Body Pigmentation
Darter, Banded6-7 saddles on back; 8-13 blotches or vertical bars not extending onto back or belly except in males where bright green bars encircle body; blotch at base of tail
Darter, Fantail9-13 faint saddles on back; 9-13 irregular vertical bars extending onto back but not belly, overlain with many thin horizontal stripes; no spots at base of tail
Darter, IowaAbout 8 saddles on back; dark mottling often with 9-12 blotches/vertical bars not extending onto back or belly; blotch at base of tail
Darter, Least6-9 blotches on back; mottled, with 7-12 small irregular blotches; blotch at base of tail
Darter, Mud8-11 saddles on back; 9-12 blotches or irregular vertical bars, often partly fused along lateral line, encircling c. peduncle; 3 vertical spots at tail base
Darter, Orangethroat3-11 saddles on back; about 8 blotches or irregular dark vertical bars not extending onto back or belly, faint thin horizontal stripes on upper sides; blotch at base of tail
Darter, Rainbow3-11 saddles on back; 8-13 regular vertical bars extending onto back but not belly, encircling caudal peduncle; no spots at base of tail
Other Characteristics
Darter, BandedGill membranes broadly attached, usually 13-15 pectoral rays; breeding males with green throat and anal fin; cheek scaled
Darter, FantailGill membranes broadly attached; 12-13 pectoral rays; breeding males with black throat and anal fin; cheek unscaled
Darter, IowaGill membranes narrowly attached; 12-14 pectoral rays; breeding males with cream throat; greenish-blue anal fin; cheek scaled
Darter, LeastGill membranes narrowly attached; usually 10 pectoral rays; breeding males with gray throat, brick-red anal fin; cheek scaled
Darter, MudGill membranes narrowly attached; usually 13-14 pectoral rays; breeding males with blue-gray throat, blue anal fin; cheek scaled
Darter, OrangethroatGill membranes narrowly attached, usually ≤12 pectoral rays; breeding males with orange throat, blue anal fin; cheek with a few scales
Darter, RainbowGill membranes narrowly attaches; usually 13 pectoral rays; breeding males with blue-black throat, orange anal fin; cheek largely unscaled
Similarity Index
Darter, BandedVery similar
Darter, FantailModerately similar
Darter, IowaModerately similar
Darter, LeastModerately similar
Darter, MudVery similar
Darter, OrangethroatVery similar
Darter, RainbowN/A
Comments
Darter, OrangethroatNot known from WI, but occurs in Illinois very close to the border, so conceivable as a stray
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