I would go ahead and start a 10-14 day Epsom salt(Not aquarium salt
) treatment on him.
Put him in a small QT container that can be floated in the heated tank to maintain temp in the 77-78F (attached to the side so it doesn't sink
) and cover the top with plastic veggie wrap to retain the heat/humidity for the labyrinth organ.
Get a clean 1gal jug and fill with dechlorinated water-Add Epsom salt 3tsp/gal and a tannin source-either IAL (1 large crushed
) or Oak leaf (20 crushed
) and let this steep for 30min and use this for 25% water changes every 15min for 1 hour today.
Tomorrow start 50% daily with the premixed treatment water....
If you used a tannin source it should look darker everyday and this is what you want.
he needs to stay in the treatment water in the QT floating in the heated tank-covered with plastic wrap for the durations of the treatment period.
Turn off the lights and keep them off-especially if you think its velvet.
Nutrition-if you have access to mosquito larva-offer several rinsed a couple of times a day
Lovely Betta by the way...
Keep us posted....