The Anemone looks healthy and fine to me, maybe its just not hungry when you are trying to feed it and its getting enough food. Love your clowns too.
Have you ever noticed the clowns feeding it by any chance?
I once had a Maroon clown and an Anemone, every morning when I fed I noticed the clown would come and get some food and take it down and spit it into the anemone. So I though I wonder what it would do if I put a small piece of raw shrimp in there if it would feet it and by dam that clown came, took the piece of shrimp right down to the anemone and fed it then came back to eat its own food, it was such a neat thing to watch I just loved watching the relationship between the two so very cool.
Just see if yours are feeding it at all, or maybe just try and offer it food once a week. Another thing is clowns are thieves too and will steel the food from the anemone as well.
See what others say but it looks fine to me, clowns always annoy anemones.