Possible fin rot on betta

I’ve had this male betta for a couple months now and he seems very happy. He lives in a 6.7 gallon tank with his temperature at 80 degrees, I tested his water just a week ago and it was perfect. I do weekly water changes and add water conditioner. He seems really happy and he still had a big appetite. However I noticed that his top fin looks like it’s ripped or frayed. It’s not very noticeable and it’s only on his top fin so i’m not sure but since his fins are so small, fin rot on him could progress really fast. All of his plants are live so I don’t think he tore them. Please let me know what you think and what I should do.

 

I’ve had this male betta for a couple months now and he seems very happy. He lives in a 6.7 gallon tank with his temperature at 80 degrees, I tested his water just a week ago and it was perfect. I do weekly water changes and add water conditioner. He seems really happy and he still had a big appetite. However I noticed that his top fin looks like it’s ripped or frayed. It’s not very noticeable and it’s only on his top fin so i’m not sure but since his fins are so small, fin rot on him could progress really fast. All of his plants are live so I don’t think he tore them. Please let me know what you think and what I should do.

Also, let me add a picture of his fins when i first got him. (Yes this is the same fish, his coloring has just changed drastically)

 

I see you don't know about the nitrogen cycle, which is completely normal. But because he has lived through it and it's pretty harsh on fish (it causes burns), he's going to look a little rough.
Thankfully, Since you have had the tank a few months, and providing you aren't throwing his filter sponge away every month or scrubbing the tank clean with chlorinated water, the tank should be cycled by now.
As the tank is cycled with clean water every week his fins should heal on their own.
How much water do you change a week? I find on smaller tanks I have to do 50% a week to keep my bettas healthy.

 

I see you don't know about the nitrogen cycle, which is completely normal. But because he has lived through it and it's pretty harsh on fish (it causes burns), he's going to look a little rough.
Thankfully, Since you have had the tank a few months, and providing you aren't throwing his filter sponge away every month or scrubbing the tank clean with chlorinated water, the tank should be cycled by now.
As the tank is cycled with clean water every week his fins should heal on their own.
How much water do you change a week? I find on smaller tanks I have to do 50% a week to keep my bettas healthy.

Hm, I just figured since I got him around August it would be cycled by now. Oh but I did actually get this new tank a while after getting him. I usually change 25%, I heard that that is best for the size of his tank I’ll start doing a 50% change instead. Also yes, I read that changing their filter isn’t good so I haven’t done that yet and I also haven’t fully cleaned the tank in a long time because I also heard that it’s not necessary if you’re doing water changes, but again I could be wrong.

 

Or instead of 50% once, you could try 25-30% twice a week. Usually helps mine get fins all prettied up.