Willster
Will
I know that the tank you got the anemone from is not suitable for it but your tank also looks brand new to me (from looking at the pictures in this thread)
If you can, get him to a more mature tank. Otherwise you just try to provide it the best you can and hope for the best.
When I wrote "lack of everything" I mean the live on LR. None of the algae and small animals we expect on the LR in a mature tank. It is possible that you got really bad LR (essentially dead rock) and have no seeded LR from some good tank or from the ocean. These live on the rock provide a lot of stability to the water condition to the tank. They process waste, both solid and liquid wast put out by the larger animals.
When the anemone have his mouth open, if you observer that the clowns dig into it, then it is best to remove the clowns. If they don't do this then it likely OK to leave them in there.
He is a beautiful Haddoni. Good luck with him
The tank is full of all dry base rock. I have maybe 2 pounds of actual live stuff in there. Not including the sand.
As for clowns I have not yet got the saddlebacks and even then, they will go into quarantine for a minimum of a month before even seeing the nem. The percula clown I have doesn't go near the nem at all. In fact the only fish that has got eaten. I am doing a test before and after a water change when the new RO filters get put in. I am just making it back home so it will be a while