I didn't know where to put this but, I thought here would be best. Sorry if this has already been asked.
My Betta has fin rot so I am going to put him in QT with AQ salt with 100% water changes for 10 days. I can't put him in a real QT tank because I keep my house very cold and I could not use a heater in a tank that small. I thought of maybe putting him in the Petco cup i got him in and floating him in the water. But that seems cruel and it might sink. So my questions are.
What can I use as a QT tank that can still be heated but isn't to big?
Also, can I just keep the pitcher of treated water out that I don't use, so I don't have to keep making new water? Thank you!