I have a male betta that I've had for 1.5 years in a 10 gallon tank. I recently noticed he has brown coloring on his head- he has always been a pretty blue & red, and his scales are significantly less "shimmery." I'm unsure if this is a disease or just him aging. Unfortunately I don't have a clear photo from when I first got him but I'm hoping it's easy to tell whats wrong from these photos. I've looked up diseases and the closest I can find is that it may be "velvet." I've moved him to a 5 gallon tank, turned the heat to 26C (78f)- its always been 24C (75f) and I've turned off his lights. and i've ordered melafix. He's happy, swimming normally, eating, being friendly (he has a big personality lol) so I'm not worried that it's an immediate emergency but something definitely seems off. You can kind of see black/brown "warts", one on the top of his head and one on the left cheek. His fins are the same as they always were (no ripping, loss etc.) I'm hoping someone can give me some advice! My other 3 bettas (all in seperate tanks) are healthy- water parameters are normal. This started to show after I bought an apple snail for him, I'm not sure if that's just a coincidence or not (the snail has since passed away) I did have a small algae problem but it was dealt with promptly. He also has a marimo moss ball in his bigger tank. thanks in advance for any advice!