So, after setting up my latest in a medium-length line of tanks, I screwed up the cycle. I added a few too many fish too early and the ammonia spiked, leading to my fish getting ammonia poisoning and looking very stressed. As an emergency measure, I put them into my aunt's tank (very mature, been running for months). I'm going to wait for mine to finish cycling before bringing them back. Did I do the right thing? I kept one of the fish in my tank because it looks especially sick, and I don't want to jeopardise my aunt's tank with it. I'm pretty sure it has swim bladder disease caused by the ammonia, so I've ordered some swim bladder disease treatment stuff and I'm going to keep up regular water changes to curb the ammonia levels while it hopefully gets better. If anyone has any suggestions, they'd be hugely appreciated. I dunno, I hope I did the right thing. I've been feeling so guilty about this - the poor fish.