Oncorhynchus mykiss (Walbaum 1792)

Material examined. 3 exemplars; 41.6 - 146.3 mm SL. CI FML 7911, 1 ex, 27° 19’ 27.29”S, 65° 53’ 20.28”W, Cochuna River. CI FML 7933, 2 ex, 27° 09’ 33.3” S 65° 42’ 37.6”W Pueblo Viejo River .

Identification. Tiny scales; lateral line scales roughly circular; 115-130 scales in midlateral row; base of the anal fin is less than half the length of the head; usually 6-9½ branched anal rays; body with black or dark spots (mainly on the dorsal region) on a greenish or coperish background; caudal with black spots at least on upper lobe, usually on whole fin; flank with pinkish to red midlateral stripe or band; no or few small black spots on opercle; juveniles with 5-10 spots (Kottelat and Freyhof, 2007; Ringuelet et al., 1961).