Sick Otocinclus?

[leroythebetta]

When I came to feed my fish, I notice my otocinclus lying on the bottom of the tank. I thought okay, he does that sometimes, take a rest. But when I came back 2 hours later, hes still in that same spot. Is he ill? My tank is cycled, ammonia 0, nitrite 0, nitrate 15. Please tell me what wrong, thanks!

 

[Cazgar]

If there are no obvious signs of illness or injuries, just keep an eye on him.
My Oto's often stay in one place for ages,