Betta fish fin rot????

i noticed that my bettas fins seem torn and there’s not anything sharp in that tank besides maybe a couple of rocks but those aren’t even sharp. He was fine yesterday and I just noticed this today. He seems very lethargic but he’s still willing to eat. Yesterday I also added some driftwood and more plants to his tank and the driftwood has a white film but that’s normal for a new piece of driftwood and should clear up in a few days. Im wondering if that had anything to do with it.
i checked my water parameters and i got 0 ammonia, .25 ppm for nitrites, 7.5pH, and 15 ppm for nitrates. He is currently in a 5.5 gal heated tank which gets 8 hours of light and is at 78°F. I did change the water a few days ago and i’m wondering if i need to do another water change or anything else to help him. any help is greatly appreciated
I apologize if the pictures are hard to see Cal was not working with me today

 

Are you dosing with Prime by chance? You shouldn't have anything but 0 for nitrites in a fully cycled tank since they're are harmful to fish. That could be part of the cause and dosing with Prime would at least make the nitrite nontoxic to fish. I would do another water change and maybe start up a salt bath/treatment for him. The algae on the driftwood is normal and harmless by the way.
here's another post on this forum that might help. mentions almond leaves you could try Is this fin rot on my Betta? | Betta Fish Forum | 510162

 

Are you dosing with Prime by chance? You shouldn't have anything but 0 for nitrites in a fully cycled tank since they're are harmful to fish. That could be part of the cause and dosing with Prime would at least make the nitrite nontoxic to fish. I would do another water change and maybe start up a salt bath/treatment for him. The algae on the driftwood is normal and harmless by the way.
here's another post on this forum that might help. mentions almond leaves you could try Is this fin rot on my Betta? | Betta Fish Forum | 510162

i usually use the api stress coat. Yea ive never had a problem with the nitrites until now and i’m not sure why it’s odd. also what is the ratio for salt to water for the salt bath treatment?

 

Keep using the stress coat and make sure you're using aquarium salt, but it's 1 tablespoon for every 5 gallons and you should dilute it in a small amount of your tank water before adding it back to the tank. Try this and see if the betta improves after a day. Then keep that dosage for 4 days or until it looks better then do another water change. If he's still not improving you'll have to look into something stronger.

You can also try a salt bath if you've got other containers or only have epsom salt Advice on giving my Betta a salt bath | Freshwater Fish Disease and Fish Health Forum | 510430

 

Keep using the stress coat and make sure you're using aquarium salt, but it's 1 tablespoon for every 5 gallons and you should dilute it in a small amount of your tank water before adding it back to the tank. Try this and see if the betta improves after a day. Then keep that dosage for 4 days or until it looks better then do another water change. If he's still not improving you'll have to look into something stronger.

You can also try a salt bath if you've got other containers or only have epsom salt Advice on giving my Betta a salt bath | Freshwater Fish Disease and Fish Health Forum | 510430

ok i will try this thank you so much!

 

ok i will try this thank you so much!

Only do the salting of the tank for up to 10 days. If he's not looking better after that, you might have to look into a stronger method. Anything more than 10 days and it's not good for the betta. Hope he gets better though!