Click in images to enlarge

Above is a 10 inch rainbow feeding just below the surface in a small Western Cape stream. I have enlarged the same image (below) to make spotting a little easier, but again spotting fish is always a case of;

Scanning the water carefully,

Keeping your head still,

Shielding your eyes from side light,

Looking for linear shadows that aren’t formed as a result of river bed stones,

Looking for movement,

Looking for the dark triangle made by the tail (not always evident)

In this case the shadow is the giveaway as far as just looking at a picture is concerned but in a small stream like this a trout sitting boldly out as this one is will be in a feeding lie, so in real life given time you will see the movement.  The answers are below.