It can take a few weeks for them to find the anemone and then instinct will kick in. I have a fail-proof trick that has worked every time for myself and customers. I know you said it is a 550 but if you can catch the clownfish and put it and the chosen anemone into a bucket with about 6 inches of water, the clownfish will go into the anemone. It is natural for them to want to hide and so they do, in the anemone. Keep them in the bucket for at least 15 minutes, then put them both back into the tank. You can encourage the bond by releasing the fish by net right into or next to the anemone.
If you try this, let us know how it goes. The hardest part by far will be catching the clownfish (assuming the anemone isn't attached to a 500lb rock at the bottom of the stack)
Good luck! :jy:
Thats fail proof?