Hi everyone! I have a beta in a community tank… I’ve had this tank set up with the current fish for almost a year now. The tank is 12 gallons. I think my betta has fin rot and was hoping for some help with what to use - Bettafix or Melafix. And can I add it to the tank where the betta lives with the 2 guppies and snail? Should I remove the charcoal filter to do so? Thank you in advance for your help!