Help! My Betta (Howl) has holes in his tail fin and the top part of it is missing. I originally had him in a 10gallon but I noticed he cut his fins on the dragon stone, so I moved him to my 5.5gallon that doesn't have any remotely sharp ornaments. He was fine for a while until I noticed the state of his fins! Could it be that his fin got infected after being moved to a different tank? (The water is slightly off color because of a piece of driftwood I put in that I have since removed because it wouldn't stop leaking tannins) The tanks water change date is today so the water color will return to normal standards so I'd like to have some opinions on if it is fin rot (none of the other fish in the tank has it, it's just him) or not and how to deal with it. I appreciate any help!