How long can corals do well without water

[Perthegallon]

Hello guys so I’m trying to drain my tank to get a dottyback fish out as this is the only possible way now but I’m worried about leaving the corals exposed to air how long can they do well without water if I do this

 

[WIReefer]

Corals should be fine if your just draining quick and grabbing the fish. I’ve had my pieces out of the water for 15-20 before and they where fine.