What happened to my Green Chromis?

[Jim Barry]

I don't think a toxin has entered the water as the corals were not affected in any way.

After rethinking it again, here is my latest theory..

I raised my alk level the other day by increasing the CO2 from my calcium reactor. When I checked it the next day, I realized I had made too much of an adjustment and the alk level had risen to 16 DKH. I think there was so much CO2 in the water the fish suffocated from lack of oxygen. This might explain why the Sailfin was "twitching" in the water before she died and why the fish died over a short period of time. Although my tank gets good O2 as a result of my overflow, sump and surface water movement, it is an acrylic tank and is covered by acrylic panels on the top. This may have reduced the amount of O2 getting into the water and impacted the ability to burn off the excess CO2.

My Atlantic Blue Tang is still hiding in the rocks and will not eat, she continually goes to the cleaner shrimp to have her mouth area cleaned.

Could too much CO2 in the water have caused permanent damage to the Tangs gills?

I have turned my reactor down and my reading is now 11.5 DKH. All the other fish are eating and appear to have survived without ill effect.

I am doing a water change this morning and have taken off the acrylic panels. I will also add a venturi to a powerhead to oxygenate the water.

Damn rookie mistakes