anyone know what this is that is causing fish death in my system? only fish that is effected are puffers see the 2 bags on top of the head? anyone have any idea the cause? Water tests fine. Every puffer I put in the system comes down with the same thing and dies with in 72 hrs, Hope the photo shows up so everyone can see. thanks kurt also I have over 80 fish in the system and all are fine some I have had for over 10 years the system is over 1200 gallons. Its a fish and live rock only system. Even if i place in an isolation cube in the system. The puffers still come down with the same thing and die with in 72 hrs. This is only related to puffers as file fish tangs angels clowns butter fly's are not effected.