'patchy' Sailfin Plec - What's Wrong?

[Metermaid]

My Red Sailfin Plec has developed patches - see pic below, does anyone know why this might be please?

 

[england]

as far as iam aware its fine, they change colour to blend in with souroundings and moods
mine sometimes goes like that

 

[JenCliBee]

they usually get patchy when stressed in 1 way or another


jen