Koi ulcers can be caused by a variety of factors, including bacterial infections, parasites, or physical injury. If you notice an ulcer on your koi, it's important to treat it promptly to prevent the infection from spreading and causing further damage. Here are the steps to treat koi ulcers:

1. Isolate the affected fish: Remove the fish from the pond and place it in a quarantine tank. This will prevent the infection from spreading to other fish in the pond.

2. Clean the wound: Gently clean the ulcer with wound disinfection or salt paste. This will help disinfect the wound and prevent further infection.

3. Apply medication: Apply an antibacterial or anti-fungal medication to the ulcer as directed by the manufacturer. There are several medications available specifically for treating koi ulcers. Our Koi Care Paramedic Kit - Koi Calm, Ulcer Swab, Propolis Wound Seal have everything you need to effectively treat koi ulcer. 

4. Monitor the fish: Check the fish regularly to see if the ulcer is healing or getting worse. If the ulcer does not improve or spreads to other areas of the fish's body, consult with a veterinarian who specializes in fish health.

5. Prevent future ulcers: To prevent future ulcers, make sure your pond is clean and well-maintained. Keep the water quality within safe levels for your fish and remove any dead leaves, debris, or other potential sources of infection from the pond.

By following these steps, you can effectively treat koi ulcers and prevent further damage to your fish.