As Confucius, the fish, suffers on the floor, two girls pick it up "like a live grenade" and return it to the tank of water. A writer of Reynolds’ caliber is careful with words. Why, do you suppose, he chose this particular simile to describe this particular moment?
Because the fish was dying it represented the grenade without its pin.Therefore you have little time to throw it before it explodes and in this casethe fish was suffocating and had a set time before it died.