Leaping Clown Fish

Checked on my fish this morning and found my larger black and white clownfish a dried husk on the floor. The smaller one is definitely distressed not that it is alone. Can I mix colors of clownfish? Could I add the regular orange and white, or do I need to look for another black and white?
Also my yellowtail damsel is making depressions in one corner of the tank. He is fanning out fairly large amounts of sand with his tail. I caught him at it the other day. I was wondering why my rocks were covered in sand, just after I had cleaned them off in a water change.
Thanks

You can get whichever color occ., black or orange, doesn't matter. Damsels like to be pain that way, making a mess of things!

Seapony, I am moving in a couple of weeks and need to sell my pair of B&W clowns. I have one that is 3or 4 years old and another (a misbar) that I got not too long ago. They have been a pair for a month or so and I hope to sell them that way if possible.
I would like 60.00 for the pair. PM me if you have any questions