So I've been dealing with my CT's down mood for a while, he's in a divided 20L tank that has 0 ammonia .. Nitrites are high and nitrates are at about 30. pH is perfect, it's heated at 26-27 degrees Celsius and he gets fed pellets every morning and a little at night.
At first I thought it was white spot which I later figured out to be his markings from baby photos, a cloudy patch appeared on the side of his head but it seems to go away as I put my flash on it. I ended up getting him to flare since I thought it'd liven him up a bit and oh, it did. My CT has issues already where his tail curls and clubs so I knew this problem and it's slowly being fixed but as he flared I noticed one of his ventrils was discoloured black with no sign of receding.
He's the type of betta who enjoys sitting on the floor to sitting on plants that are provided, so I'm not entirely sure if its injured or fin rot. Both are being treated with salt since the other boy enjoys being vigorous and fin flaring and since the white spot appeared they're both being treated with a fungal remover. (Just incase my other boy got in while tank sharing)
Both act normal, both feed. He's less active then Cinderella but he's older as well. Any ideas?
Update: I found another black ventril that has curled/clubbed. His other ventrils are reddish from the clubbing injuries he sustained.