youre going through what's called a bacterial bloom. It can happen when you stir up substrate. Don't worry about the cloudy water it'll go away soon. I would be worried about that pleco and Cory. The common pleco would grow way to big for that tank, and Corys need to be in a group of atleast 6. Swap the common pleco for a Bristlenose pleco those max at 5-6"