Keep the water as clean as possibile daily 50% water changes and salt at 1 tablespoon per 5 gallons of water. You can also swap Methylene Blue directly on the wound to prevent secondary bacterial/fungal infection from taking hold and facilatate healing. Clean, clean water is the key here above anything else. Also look for what might have caused it, remove anythig with sharp edges or bulllying tankmates that may have caused it to dart away cutting itself in the process. That ceramic tile looks like it could do some damage.