Strange behavior in my corys should i be worried

[Cardex]

I got home from work tonight and found 4 of my corries hanging out on top of one of the rock caves they have moved a little but mostly trading places on the rock for the past 2 hours no visible damage they are not gasping for air reading are normal 0/0/0 (I have to add nitrate ferts) no recent changes to the tank and the only fish that are acting odd are the bronze corries

 

[ShinobiFishKeeper]

Have you tried feeding them? My corys just stay idle in a hiding place and once food is present they quickly start to move around