Hi! Although I am still a new member, I have been doing
betta rescue for a couple years now. He definitely has a bacterial contition called fin rot . It looks pretty moderate to severe, especially if he doesn't have energy and he is lying on the ground constantly as you mentioned. As I have found out with bettas, never use a heavy medication (antibiotic, antI fungal, antiparasitic, etc) unless YOU ARE ABSOLUTELY POSITIVE you need to. Hard medications often can promote adverse effects. Instead, I like to use clean, warm water, combined with
aquarium salt and Indian
Almond Leaf if I can. Sometimes I add in
Betta Revive as well, as it's a medication that is not too strong but does help with cases like this. I would do all of these things with your betta.
P.S.
Betta fix (and usually anything with 'fix' at the end, is just tea tree oil extract. Although there have been accounts of it helping fish, with bettas it can coat their labyrinth organ, making hard to breath.
Betta Revive:
Indian almond leaf (I always have this, and I use it for all my bettas):
Aquarium salt:
Sidnote: I know you will do everything to prevent this, but if he does die, don't beat yourself up. It's hard, I've lost way more than I like to think about. But these creatures can be fragile and sometimes even though we do our best they still go.
I'm sorry, please do not do this. There are no indicators of parasites and treating for it may do more harm than good