odd fish behavior

[busymom]

I was wondering what would cause a fish ( in this case a tomato clown) to constantly hang out behind the lip of a hang on filter where the water is flowing back into the tank. Does it have something to do with the current in the tank. I thought at first that it might be temporary hiding spot or a "safe feeling" sleeping spot but he really doesnt come out from behind there. I have plenty of live rock/hide out spots in the tank and my filter/skimmer is turning 400g/hr in a 29 gal.
Thought I would also post this on the clown board, is this just a wierd clown trait?

 

[weberian]

The only thing that I have read lately that relates in any way to your situation is that some fish are forced off into upper corners or sides of the tank from other agressive fish that want to protect their territory.