Lost twelve fish in the last two weeks. Have five left. Looks like they r eating and moving around just fine. Dead fish didn't look bad either. Checked water parameters and everything is good. Do twenty percent water changes every week using tropic marine mix. Only thing I've changed is how I feed. Was feeding rod's frozen as the primary food and supplementing with pellet and flake. Switched that around. Now feeding mostly pellet and flake. Don't know if I'm starving them or something got into the tank and I'm slowly poisoning them. I'm all out of ideas.