I have some questions related to rearranging stock and tanks. I have just been given a 4 foot tank off a mate who broke up with his girlfriend and selling their house. He wanted someone who’d take care of his 3 year old Cichlids properly. It has a Green Terror and Blue Acara in it. I also have an 85G 5 foot tank that currently houses 4 Rainbows, 1 Opaline Gourami, and 4 Coreys but two Rainbows have a bacterial or fungal infection that I’m trying to get under control so have been treating the whole tank (Tri-Phos...something or other tablets for fungus). I also have a 20G tall with an Angel, Opaline Gourami and BN Pleco. My plan is to swap the fish in the 4 and 5 foot tanks and also add the fish from the 20G to the 4 foot tank so I can use it as a quarantine tank to properly treat the rainbows and use for quarantine for future fish. I want to ensure I minimise stress and don’t infect the Acara and GT when moving them to the 5 foot tank. I hope this makes sense. Please ask questions if I’ve not explained myself properly. All of my tanks are cycled but the 5 foot tank is still fairly new (2months). 4 foot tank is cycled but has very high nitrates due to infrequent water changes but that will be rectified when I drain for transport and then refill. I guess my concerns are will the filter or décor of my 5 foot tank potentially carry whatever my rainbows have? Can I just swap all the fish without also swapping water if I acclimatise them properly? Will a 50% water change on the 5 foot tank be enough to reduce the amount of medication in the tank for the GT and Blue Acara? Sorry for the long blurb.