Lately, his colour appears to have dulled, and he no longer eats and doesn't even notice food being dropped in. He spends most of his time lying on his side at the bottom of the bowl. When he does move, he appears to have some trouble swimming upwards and stay up.
I've had my betta fish for almost two years now. I haven't changed his set up very much in this time. He's housed in a 1 gallon sized bowl with room temperature water that I let sit for a day before putting him in. I change it around once every 10 days switching between 2 bowls. I have a fake plant which my fish normally enjoys to rest in, between the leaves.
I have no idea what to do. I moved him into my room from the kitchen where there's more light and is a little warmer. He responded that for a short time, but now it's the same thing.
This is my first time on this forum, and any advice would be extremely helpful.