My silver aro, 12” long is sitting at the bottom of tank since my aquarium cleaning.I took him in a big plastic cover . Cleared the aquarium well. Filled up with water and around 20mins after i introduced him.! And from around 2 weeks he is like this. He only comes up when i go near him to feed. Rest all time he sits at the bottom near the filter.. please help..! Before my aquarium water changes he was well and active. Know he seems to be lil scared because he jumped when i was trying to get him into cover..