Rainbow Smelt
  • Side view adult.
  • Side view adult.
  • Side view of two adults.
  • 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 tail region: Notice the presence of an adipose fin.
  • Close-up mouth: There are teeth on the jaw and particularly prominent teeth on the tongue.
  • Close-up mouth: Notice the teeth in the jaws.
  • Close-up tail: The tail shows dark pigment.
  • The rainbow smelt has an elongated, silvery body, a large terminal mouth, and an adipose fin.
  • Close-up pelvic fin: There is a lack of an axillary process on the dorsal side of the origin of the pelvic fin.
  • Alternate side view showing the particularly elongated shape, translucent body, and limited scalation.
  • Alternate side view of a juvenile showing the particularly elongated shape, translucent body, and limited scalation.
  • Side view of a juvenile showing the particularly elongated shape, translucent body, and limited scalation.
  • Close-up of the head region showing the particularly elongated shape, translucent body, and limited scalation.
  • Alternate side view of two adults.
  • Alternate view of the tail region.
  • Alternate side view.
DescriptionSimilar Species
Family
Smelts (Osmeridae)
Body
Mouth and snout: Terminal, large and slightly oblique, with prominent teeth on the upper and lower jaws. No barbels. Body patterning, color, and scales: Solid color; light olive or tan back, silvery or gray flanks, whitish belly. 62-72 cycloid lateral line scales. Fins lightly pigmented, except posterior part of tail, which is darkly pigmented. Body shape and size: Body fusiform and elongated; oval in cross section. Typically 100-200 mm (4-8 in) TL; maximum about 375 mm (15 in).
Fins
Tail, dorsal and other fins: Forked tail. Single dorsal no spines and 8-11 rays. Pelvic fins abdominal without axillary process. Adipose fin present. Anal fin with 12-16 rays.
Distinguishing Characteristics
The rainbow smelt can be distinguished by its prominent jaw teeth and adipose fin, elongated body, and the lack of an axillary process associated with the pelvic fin. See also similar species information.
Breeding Adults
Males have fine tubercles on head, body, and fins.
Juveniles
More elongated than adults, with a translucent body and limited scalation (photos).
Hybrids
None known from Wisconsin.
No similar species.
Compare Similar Species
Comment
Smelt, RainbowThe rainbow smelt is moderately similar to cisco and whitefish (Coregonus and Prosopium) and shiners without a dark lateral stripe (Notropis and Hybognathus). It can be distinguished from shiners by its prominent jaw teeth and adipose fin (lacking in shiners) and from cisco and whitefish by its prominent jaw teeth (vs. less conspicuous), more elongated body (vs. deeper body), and lack of an axillary process associated with the pelvic fin (vs. present).
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