Can you post pictures. Losing color as in not as bright or male to female changing? Is he healthy and fat? IIt would be very strange for him to change sex because 315 is hardly the natural range of the male angel. I guess you can add another female to stimulate him. Make sure he is at optimal health include consider treating him for internal parasites.
Sorry I should have been more clear, he is very healthy and nice and fat. He has lost his vertical stripes and the yellow bar down his side. I have to look hard to tell the difference between him and the original female. The only distinguishing features are a little remaining yellow around the nostrils and slightly larger size.