I got a turquoise betta fish from Petsmart less than a month ago. Since then, he has been acting strangely. When i first got him, he had a few scales under his chin that were bright yellow. I dismissed this as his natural coloring and took him in. He was really shy at first and liked to hide, and it took a while for him to eat (pellet) and he spit it up a bit while eating. So I kept him in a cycled 1 gallon tank for two weeks (water change every weekend), and recently upgraded it to heated, cycled, 2.5 gallon. As time progressed, the scales around his face kept yellowing, and its increased it’s area around his face. He has also lost some of his vibrant colors, and started twitching two days ago. He also really likes to be between the filter and the heater for some reason, I’m not sure if that’s normal or not. If anyone could tell me if there’s something wrong or what I could do, I would really appreciate it.