Brian-

I really wouldn't worry about the clown. As long as he/she is eating well, that's the most important thing. When I add a new fish to the tank, it seems that it takes about a week before they are more relaxed and comfortable in their surroundings. I'm sure your clown just feels safer in the RBTA for now. Can you post a pic? How is the clown breathing? Slow and normal, or does it appear to be "panting"? Keep a close eye on the breathing and also on the body and fins of the fish for any signs of disease... ;)

Wendy