Yesterday I found my common goldfish stuck onto the intake of the filter. (It’s the tetra whisper internal filter for 10 gallon tanks.) I thought he was dead but I got him off and he surprisingly swam away. Last night he mostly stayed in one spot at the bottom of the tank. This morning he was able to swim almost normally but he mostly rested near the surface in one spot. He is now resting near the surface but laying completely sideways on his left. I’m wondering if there’s anything I can do for him? I assume he has swim bladder but I honestly don’t know. I moved him to a smaller tank with a weaker filter while he hopefully gets better. Any help appreciated!