Hi, I have a new setup, the tank was set up on Sunday and I had 6 fish put into the tank on Wednesday, one of these fish has now developed red spots and is swimming at the top of the tank. Looking on the internet this seems to be ammonia poisoning? I have done a partial water change to try and rectify this. The readings from my water test are as follows: No3 20 No2 0.5 Ph 7 Kh 80 Gh 180 Any advice on what to do now? Do I remove this fish or what?