When corals start to rapidly decline in your aquarium with no obvious reason in sight, there are a few paths to take to prevent all out destruction. For one, don’t lose your cool and panic. Chances are that the problem is simple and fixable. Once you’ve gathered yourself, prepare and perform a water change. This will dilute any chemicals or metabolic byproducts that could be harming your corals. After a big water change, add carbon to your filtration scheme to further remove any harmful pollutants that might cause damage. After these two important steps, start trying to find the source of the issue all the while prepping for more water changes. Check every piece of equipment in use to eliminate voltage issues. Then make sure there is nothing within the tank that can be releasing harmful chemicals. If none of that works, try bouncing ideas off of fellow hobbyists and keep troubleshooting until the problems are resolved. It may take a while, and you may lose a lot of livestock, but acting quick and being smart are key to ensuring that you minimize those losses.