Well, I had something simple go wrong, My 350 gallon display was doing great, new tank syndrome - lots of cyano, but, I had spent 3 months adding 19 fish. They were all thriving until one day. my most recent additions - anthias, started dieing. 2 in one day were just missing. I was irritated, but, I know anthias can be delicate. I increased my feeding regime, and did the best I could to give them a nice home. a couple days later 2 more were dead. No signs of anything wrong with those still alive. Nothing at all. Those still alive were eating and swimming healthily. Then 3 disappeared.
Then it wasn't just the anthias, I lost my cardinals I had had since the beginning, they were the first fish. My clown fish died, and I knew I had a real problem. It was spiraling out of control. However, it was too late, 14 fish out of 19 fish died. I felt extremely horrible. This had to be my fault somehow. Was it disease? Could I have treated? Was it something else. I worked with my LFS. I was so confused because if it was water contamination my corals should be dieing... they weren't. They were growing... Faster than I've ever seen any corals grow. So, it wasn't the water in my opinion.
Then, I checked electrical, touched something grounded and put my hand in the sump, my hand vibrated from the continuous shock going through it... I turned my heaters off, it stopped... I had a bad heater, electrifying the entire tank. Hard to say when it went bad or what, but, must have been around the time I added the Anthias. Some fish had marks on them, my rabbit fish, which is still alive, had obvious signs of flukes or a parasite. Just a couple sticking out the side of him. I felt horrible and angry!
I replaced both of my heaters as a result and haven't added any fish since then. I'm going to let the remaining 5 heal from their electroshock therapy and feed well, and make sure everyone is happy before adding anymore fish. The tank looks void of life right now a 350 gallon display with 5 fish. and maybe 20 corals.....