Hi everyone! I was looking for some fish advice on my Opal Male betta, Kodak. He is about 5-6 months old, and when I got him, he had a very tiny white spot on his body. Although, since I got him, it has been growing (very very slowly). It started as a grain of salt, but now it is about the size of half a pea. I have been scouring the internet for figuring out what this might be and how to treat it. However, I can't grasp what exactly it is since it is only on one spot on his body. I am almost positive it is a fungal infection, but I want to double check with any help/advice from here to make sure I am going to treat the right thing for Kodak.
He is energetic, but not as much since I got him. He likes to rub himself on the decorative plants I have in the tank. I also noticed he is becoming more lethargic lately, and has himself stay in place most of the time by mostly resting in the parts of the tank that have little current, like inside of his pink rock. I appreciate any advice and/or help to what this could be and how I should proceed.
I checked the levels today after a partial water change yesterday:
pH: 7.1
Nitrates: 13 ppm
Hardness: 82 ppm
Nitrite: 0.75 ppb
Ammonia: 0
KH/Buffer: 7 dKH
Water Temperature: 79F
I have attached a clear picture of the growing spot, and it is now beginning to grow outward. Before that, it was flat and had no texture. It has only begun to grow outward from his body in the past couple of weeks.
Both pictures are from today, for one he is in the light and the other is the shadow of it which clearly shows its shape. Thank you.