Had to be a Acan eating worm or something! Because Every Acan I lost, died when every thing was healthy, then right after one died, another one would start to die. I would say thats what happend to about 6 of them, because I lost three or four to some peppermint shrimps! don't tell me that it wasn't the shrimps! I saw them with my own eye's! I think it was because the shrimps could smell the mysis that I feed my Acans!