I think i'm dealing with that prob ... I've had three fish go crazy by swimming erratically bashing off the top of the tank, sides, swimming upside down and after they seem out of it. Looks like they had a seizure then after a bit seem fine ..two fish have died and my syn I've had for a couple months now is doing it but the fish that have been in there for a long time are fine.. all my params are perfect..I'm really confused so if anyone knows anything about it plzzz help me out..