If you have a community tank with several fish, you'll need to remove your sick fish to prevent any bacteria, parasites, etc., from spreading to the others. Prepare a separate tank to use while treating your betta for dropsy and while they recover. Treat the water with aquarium salt. Add about 1 teaspoon per gallon of water to the quarantine tank.Body Fungus. Body fungus -- despite the name -- can infect the gills of a betta. The fungi that cause it belong to the related genera Saprolegnia and Achyla. This true fungal infection typically looks like whitish cottony growths. The strands may pick up colors from debris, giving them other colors. You can treat this infection with antifugal
Yes, give him his heater. But as columnaris thrives in heat turn it down a bit to 74 or so, which is the low end of comfort for bettas.. but IF it is columnaris, it'll slow the progress of the disease. If not, then he won't be too cold, just a little bit less warm than usual. PLANTED TANKS: AKA UNDERWATER JUNGLES.
About 12 mg/l will treat a saltwater fish for up to one hour and a freshwater fish for up to 10 minutes. A dip can be as high as 50 mg/l for duration of 10 seconds. Potassium Permanganate. Permanganate will eliminate anchor worms, fish lice, flukes, ick, cotton mouth, fungus and many bacteria.