Whats wrong with my fish?

recently we had a power outage and my Black Moore (Sheldon) wasn't dealing so well with it.. he was on his side at the top of the tank 'gasping' for air i assume.. though our other fish which is just a common Goldfish was fine.. we removed them to some fresh water and had brought them to our neibhors... show more recently we had a power outage and my Black Moore (Sheldon) wasn't dealing so well with it.. he was on his side at the top of the tank 'gasping' for air i assume.. though our other fish which is just a common Goldfish was fine.. we removed them to some fresh water and had brought them to our neibhors since they had electricity and the filter would work. next day checking on him he was fine and appeared okay. later that day he was at the bottom of the tank very lethargic i assume stress.. our other fish is still fine and a few days later now he is still at the bottom of the tank.. will he be okay? what should i do?
Update: I used aquarium salt/stress coat to make the water safe i even reduced feeding.
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