I had a tomato clown that acted similar once. When I first got it he stood in the top corner of the tank for a week, then was completly vertical for a full day I thought it was dead. After a few more days it either got better or snapped out of it because it became a great addition to the tank virtualy overnight. I remember it made me nervous the whole time. Hope it is just in shock and not getting sick.
Hope this helped
As Lando says, definately need more info. Water parameters, how long have you had the fish, how was the fish acclimated? Your info button says there are three other damsels in the tank, any aggression issues from them?
All water parameters are 0 or near 0. The fish is only a week old. both of the clowns were acclimated by adding aquarium water 1/2 at a time 4 times. The little guy seems to be acting normally now. Every once in a while he will get near the bottom but he still eats and has no physical signs on any problems. Maybe he is just getting used to the new setup.
The yellow tail damsel is picking when the clowns or the blue cromis gets near his "rock", but otherwise he is not pursuing them. The clowns seem to be unconcerned with him. Currently, the abovementioned clown is along the back side of the tank on the sand and not moving a whole lot. I am just curious how I can tell what is wrong with him. My QT tank is almost cycled. Maybe I should put him in there?
I don't know unless he has outward signs of illness. Marine velvet is one of those diseases that will cause a fish to become lethargic and won't show signs until the fish is almost beyond repair. I would move him to the QT tank to monitor him for a few weeks. There is an article on marine velvet in the articles section. Here, it is...