I wonder if fish are afraid of fireworks like some dogs and cats can be? Drop something noisy close to a tank and the fish will suddenly dart away; I wonder if fireworks do the same thing to pond fish?
My latest dog of four months seems unfazed by them. My last dog would crawl under the bed and be inconsolable until they'd stopped. The previous dog that was ok if you took him outside to watch but hated to hear them indoors; odd.