So i had a siberian sturgeon for at least a good two months now with no issues whatsoever. His personality was to swim in spirals and barrel rolls throughout the tank was his normal behavior. But now just today I looked at him and he was just laying at the bottom, which he never did and it was always an active sturgeon so I never saw him rest at the bottom before, not only that, his right eye is now opaque white!! The only things that I did to the tank was feed them fish flakes instead of there original bloodworms yesterday, and added new fish. So any helpful tips will be helpful!! Thank you for your time!!