They normally move all around the tank and sometimes sit in an area, I have seen them up top but no spending this much time up top. They fed normal and dart back to the middle of the tank if I go near them, could it be the just take a rest behind the filter currents? I added a second filter yesterday.Do they not usually do this? My barbs roam all over my tank, and come up to the very top when I get near it, hoping to be fed. If they seem fine otherwise, I wouldn't worry.