Hi, one of my axolotls (Aristotle) died this morning. He had been sick the last few weeks, floating, not eating and just generally looking distressed. I took him for a holiday in the fridge, and he got alot better. He started eating again and I moved him back to the tank with my other wild type (Plato). The tank parameters were all fine during this period, He had seemed fine over the last few days, in fact I was very relieved that he got so much better. I got back from shopping this afternoon to find him dead, sunk, and upside down on the bottom of the tank. My other axolotl was floating and didn't look at all happy. I've removed the remaining alive one from the tank, and into a small dish for the time being, just to escape the nasty tank water created from Aristotle. My question is, how do I go about putting my still alive fish, back into the normal tank? Is a 100% tank water change needed? I'm so confused, I know that dead fish release lots of bad stuff, but I don't know what I should do to get my live fish back into that tank. Sorry for the depressing news.