the one fish you are holding by the gills has been killed?
from gov.bc.ca site
Holding a fish by the gills can cause damage to the gills.
Releasing Fish – The Gentle Way
There is a growing trend among anglers to catch and release, unharmed, a part of their allowable catch. As well, more restrictive regulations on specific waters can severely limit the angler's allowable harvest. A fish that appears unharmed may not survive if carelessly handled, so please abide by the following:
Keep the fish in the water as much as possible. A fish out of water is suffocating. Internal injuries and scale loss is much more likely to occur when out of water.
If you must handle the fish, do so with your bare, wet hands (not with gloves). Keep your fingers out of the gills, and don't squeeze the fish or cause scales to be lost or damaged. It is best to leave fish in the water for photos. If you must lift a fish then provide support by cradling one hand behind the front fins and your other hand just forward of the tail fin. Minimize the time out of the water, then hold the fish in the water to recover.