My betta Roger has had a growth on his back for a few months now. Originally I thought it to be ich but treatment with rid ich did nothing and he lacked the sandy coating. Assuming it was a fungal infection I have been treating with Pimafix but the growth has gotten bigger. I am not sure if his condition is treatable or if it is a sign of his age. I have had him for 4 years and he has been healthy up until now. He's also, still pretty energetic and swims all over the tank.
Sorry about the poor photo quality, I took the photos with my phone.
Also, I have been conditioning the water with stress coat and doing weekly water changes. It's only a 1 gallon tank, which is the largest tank I can fit in my meager apartment right now.