This happened so fast last night when i went to bed my bala shark was fine and normal and this morn i woke up and he was swimming around kinda wierd. His tail was floating to the top like he was going tail over head. I went to the fish store to get my filter materials to do a water change on my other tank and when i got back he was really strugling to swim. I put him in a quarintine tank and treated it with salt and pima fix and for awhile all he did was sit on the bottem upside down curled in a C shape. Then for a bit he was swimming around really slowly but upside down and now hes back to being on the bottem. Whats wrong with him all my water conditions are fine i just checked them thinking maybe he was stressed. Also on that about a week and a half ago my tank was leaking and i took all my fish out into a big tub and siliconed the leak. I used an aquarium silicone and let it cure for around 36 hours befor putting my fish back. I have florolite red in my tank and for anyone that has used that im sure u know how merky it makes the water for the first few days. I couldnt see 2 inches into the tank and when i would see my bala u could see he wasnt acting normal then but since then he was perfectly fine until now. Dont know if that maybe had something to do with it as well.