Can anyone tell me what actually happens when a fish goes into shock. I've twice rescued a PJ Cardinal Fish who'd been attacked by tank mates. I happened to be there and saw him floating by, upside down, not moving or breathing; pale; stiff; drifting into the rocks. I netted him and put in in the ER tank to die in peace. More than an hour later he was still floating around bumping into stuff like he was dead. Next morning, he swimming around - both times. JKJ