White spot behind dorsal of Betta

I noticed a small white patch behind the dorsal fin on my betta. Seems like it's been there for a while, but it was very small. Now I notice it's larger. Does anyone know what this is? He's about 1.5 years old...a mature fish for sure.

 

Maybe possible fungus, i can't tell for sure on fungus stuff in pictures.

 

Maybe possible fungus, i can't tell for sure on fungus stuff in pictures.

It doesn't look like a cotton ball. Just a patch of white on the scales.

 

Any suggestions how to deal with this problem? I don't want the Betta to decline in health. Should I get anti fungal treatment?

I change his water all the time. Most day 25% per day. Sometimes I skip a day.

 

May be worth it. Something like ich-x might be good, it is also a fungal med.

 

May be worth it. Something like ich-x might be good, it is also a fungal med.

I'll give it a try. Thank you!

 

I gave the tank the first dose today. Not sure how I'm going to follow the instructions though. It says to keep dosing for 7 days and then do a water change. I do 25% per day water changes...this is a 2.5 gallon tank. I don't want to go a week without a water change.

Maybe the strategy would be to up the dose a little bit since I'm taking some out every day...

 

I dont really mess with meds at all

 

Do you have any sharp decorations in your tank that he could have tried to squeeze past and possibly scraped his body on? If it’s not fungus then it could just be something like that.