Clarkii Clown Changing Color

[wam67]

I have a large blck Clarkii clown and I added a small orange clarkii clown (identical markings except he was orange) They have been together about 4-6 weeks and paired up almost right away. Side note: ( They also abandodned the sebae nem they were in and moved into a large green carpet . The little clown sleeps in the mouth of the carpet.) I noticed last night the small clown has now turned black just like the big female. I was wondering if this common. The color change literally happened overnight. He was orange yesterday. Really interesting. I have a thing for clowns and nems. Thanks Bill