My male betta has only been with me for three months. I did a 20% water change last week, and about four days ago, he became very sluggish. He stopped swimming around and sometimes just hangs out in the corner. When this began, there were some live plants in the aquarium--he's in a 1.5 gallon tank. He was eating very well before, and now he just looks at the food. He might eat one worm, but doesn't finish more than that. He has become very pale, and he's not very reactive at all. I don't know what to do. I've taken the live plants out of his tank and did a 10% water change yesterday. Today, he's not hiding in the corner, but he's still very pale and sluggish, and non-responsive. What should I do?!?