I put some more pictures here to answer Ekonas question from this thread.
These photos all show the same male:
Two pictures taken at the same day with the same camera:
Same fish, about one year later:
Another month later, still the same fish:
And it is the fish shown in my avatar!
I once thought there might be a difference in colouration depending on the age of the fish – but I now think it is a matter of light. It’s a characteristic of these structural colours – contrary to pigment colours – that they never seem the same under different light incidence.