clowns acting very odd

i just bought a pair of adult? percula clowns...( captive bred... petco)problem is these guys do not go to the bottom of the tank ever!! not even near the 50 pounds of live rock..... i have had them for 3 weeks..they eat very well i have a condy anemone and a plate coral they dont even look at them, i know the clowns wont host either...but i never had clowns swim only at the top of the tank they sleep behind the power filter...by the way its a 38 gallon tank.. all water parrameters are excellent and they are the only fish in the tank besides the plate coral cody anemone and cleaner shrimp...any ideas guys?? or do i have a pair of odd clowns??? ciao derick

just at the water column ..they have never ventured near the bottom of the tank..