Ok I just started my aquarium a few weeks ago. I used live sand and live rock. I gave it 2 weeks to cycle and I started simple by adding a few damsels. My fish keep dying and I can't figure out why. On a side note I did find and remove one large bristleworm and 4 small ones from the tank. But even after that the fish aren't making it. I've been testing the water and haven't found a good reason for what is going on.