Scales

Brown trout are one of the prettiest fish. Although they are called 'brown', the markings are different on every fish you catch. Some are a butter-yellow colour and others are silvery with very red spots. Some have large round and dark spots, some have hundreds of smaller ones. Many of them have bright red spots in perfect patterns down their sides.

All of them have these tiny soft scales, which reflect light with the most amazing rainbow colours.

I didn't really manage to catch that amazing iridescence and I know this pic looks 'noisy' but the very tiny dots are the pigments in the scales that form the spots and patterns.

Sorry that's not very interesting to most people, but to me they are one of the most beautiful creatures (also great fun to catch, and grilled with lemon and pepper, on a piece of toast...they taste fantastic!)