First time I had seen in the Tarrago river: local fishermen told me they were not there. The second fish is behind the branch wood and is smaller. They seemed to be breeding: the big fish (shown, about 35-40 cm) was visited by the smaller (25-30 cm) fish repeatedly. The smaller fish would the go into the weeds at the rivers edge for a minute or two before repeating the visit behaviour. The heavy scales and reddish ventral fins are diagnostic in the photo, but the species was clear to the eye.