Adding sand after the fact question

[Aquattro]

Originally Posted by fishoholic

When I was googling info on it I found an article that said this "If you are using LR in the tank, you should not pour the LS over or on top of it. The sand will cover and smother the LR causing oxygen depletion, resulting in the death of it." I figured if the sand could smother my rock and deplete oxygen it, then it would be the same for the fish and water

Yup, do not pour sand over existing fish, it will smother them