Hello, my betta fish, Reef has had fin rot for over a year. Over the past few months, (6) I have been able to stop the fin rot. His fins even started to grow back a little. However, I put him in a new 20 gallon tank (do 15 because the water evaporates and is not filled to the top) and a month later, the fin rot has been shredding his fins. I use API betta fix to treat his fins, but I really am worried this would progress into body rot. The betta fix used to do its job properly, but now all it does is stop the fin rots rapid progress. I I miss a day of putting medicine, his fins would be devoured a whole bunch. All my parameters are fine, and I have no sharp objects in the tank. There is a filter and heater, a couple plants (I can’t get live ones), two logs, a coral reef decoration, and an air bubbler.