• Side view adult.
  • Side view adult.
  • Side view adult.
  • Top view adult.
  • Bottom view adult.
  • Head-on view adult.
  • Close-up flank.
  • Close-up head.
  • Close-up mouth and snout.
  • Close-up tail.
  • Close-up dorsal fin.
  • Close-up anal fin.
  • Close-up pectoral fin.
  • Close-up pelvic fin.
  • Close-up flank: Notice the spots or small blotches on the flanks.
  • The dorsal fin consists of two dorsal lobes and is spotted; there is no adipose fins; the flanks are spotted as well.
  • Close-up dorsal fin: There are two dorsal lobes, the first (spiny) lobe is very high and there are membranes between the spotted spines.
  • Close-up head: There are 5-10 spines on the preopercle.
  • Juveniles are similar to adults, but are less deep-bodied and the flank spots are bigger and more blotch-like.
  • Juveniles are similar to adults, but are less deep-bodied and the flank spots are bigger and more blotch-like.
  • Alternative side view of an adult.
  • Comparison of yellow perch (top) and ruffe: Notice the different pigment patterns on the dorsal fin and flanks.
DescriptionSimilar Species
Perches (Percidae)
Mouth and snout: Mouth terminal to slightly subterminal and oblique, with minute teeth on the jaws. No barbels. Body patterning, color, and scales: Tan, olive, silvery or gray, with irregular dark spots or small blotches or mottling, mainly dorsally, often faint. Belly cream or white. Dorsal and tail fins spotted, other fins clear or whitish. 34-40 ctenoid lateral scales. Body shape and size: Body fusiform, laterally compressed and deep; oval in cross section. Typically 100-150 mm (4-6 in) TL; maximum in Wisconsin about 225 mm (9 in).
Tail, dorsal and other fins: Forked tail. Dorsal fin with 2 lobes, attached by a membrane, the first with 11-18 spines and the second with 1 spine and 11-16 rays. Pelvic fins thoracic; first ray elongated into filament. Adipose fin absent. Anal fin with 2 spines and 5-8 rays.
Distinguishing Characteristics
The ruffe can be distinguished by its long dorsal fin with two distinct lobes, its lack of an adipose fin, its thoracic pelvic fins, its spotted or mottled flanks, its spotted first dorsal fin, and its 5-10 spines on the preopercle. See also similar species information.
Breeding Adults
Similar to non-breeders.
Similar to adults, but less deep-bodied (photos).
Compare Similar Species
Dorsal Fin
Perch, YellowLong with two distinct lobes
RuffeLong with two connected lobes
Trout-perchShort with one lobe
Adipose Fin
Perch, YellowAbsent
Position of Pelvic Fin
Perch, YellowThoraic
Body Pattern
Perch, YellowDark vertical bars on yellowish-green background
RuffeSpotted or mottled flanks on yellowish-green background
Trout-perchSpotted/blotched on silvery-olive background
Similarity Index
Perch, YellowModerately similar
Trout-perchModerately similar