I have a two-part question, because I have two saltwater tanks that are in trouble. One is a 40 gallon tank that's been set up for about 8 months. I slowly added fish and corals and it was looking great. I have a large whisper filter running this tank, as well as a powerhead on one side. I had a bunch of damsels, coral beauty, butterfly, and a yellow tang(which i know was a mistake), snails, crabs, and a few mushrooms. I test my water regularly and do a small water change every two weeks. Everything tested fine. I now have a qt
tank, but I didnt at the time. One day, the yellow tang died, about 2-3weeks after I got him. I took him out, then 2-3 days later, all the other fish died. They werent eating, they werent swimming very much, no scratching against the rocks, no big change in discoloration, nothing growing on them, no spots or anything, just died. Everything died except the mushrooms, the snails, crabs, and a brittle star. Now, 3 weeks later, the mushrooms are blooming, snails and crabs are all over that tank, but when I try to add a couple damsels after putting them in a qt
tank, they die within a day. I don't know whats in the water that allows inverts to thrive while fish cant last a day.
My other tank is a 54 Corner. And the same thing, I slowly added fish over 6-8 months, til I had some damsels, a clown, 4 green chromis, and a lemonpeel angel. I have a big canister filter running this tank and I use R.O. water when I do water changes. The lemonpeel angel lasted a couple weeks, and he had been in the LFS
for almost a month before I got him. He was eating, swimming around, acting fine, then dead the next day. Now, almost a week later, all 4 chromis died, and the clown and the blue damsels arent swimming very much, but they're still eating, but the snails and crabs are doing fine. Does anyone know what I can do to save these fish? Is there some medication that I can put in the water that's like a "cure-all"? Or something? anything I can do or am doing wrong? I'd really like to save these fish. Please help