Photographing wild brown trout

My book is about the whole environment of the chalk streams with the rich variety of wildlife. It is not a fishing book, but should, of course, include images of one of the iconic species - wild brown trout. However, this has proved to be more of  a challenge than anticipated as I wanted shots of them in their natural habitat, not in a net or handheld. Many attempts photographing them from the bank or bridges proved to be unsatisfactory because of reflections (although some can be eliminated by the use of a polarising filter) or the refraction of moving water giving a blurred and milky picture. It took a crystal clear stretch of the upper Itchen and bright sunshine at the right angle to get the image above which will probably appear in the book. I rather like all the colours and patterns created by the light on the clean gravel on the riverbed.
Some of the other images of fish I have shortlisted for the book were taken while wading with a waterproof compact camera. Again, it took the right weather, light and clarity of water to get acceptable outcomes - and the rejection of vast numbers of out of focus or badly composed efforts!