Melafix (or Bettafix or Pimafix) should not be used in a tank with any labyrinth fish as the aromatic oils they contain can coat the labyrinth organ.
Methylene blue was mentioned in an earlier post - please be aware that this will kill the filter bacteria and stain everything blue.
Methylene blue was mentioned in an earlier post - please be aware that this will kill the filter bacteria and stain everything blue.