The trouts pictures are from Argentina (Filo Hua Hum river), during summer the banks of this small river are full of hoppers so this pattern is very good for jenuary and february. The last picture is a baby dorado (Salminus Maxillosus).
We don't have trouts here in Uruguay, we have fresh water dorados and tarariras, both are toothy and very agresive fish.
Dorados and Tarariras are fished mostly with streamers and poppers also work very good for the tarariras. We have two kind of tarariras, the black one, very sportive and bigger (Hoplias Lacerdae) and the common one (Hoplias Malabaricus).
This is a picture of a typical river from my country.