I was doing a water change today on my nano and took out the rocks to scrub the hair algae off them. I dumped the dirty water into the toilet and flushed it. It hadn't stopped running after a couple minutes so I went back to the toilet, jiggled the handle, and lifted the lid to check and see if all the mess had gone down and found my little fishy! I quickly, without hesitation, scooped him out and dropped him back into the nano. I hope he survives!