Do zoas melted away for no reason at all?

[kingpin9995]

I went on vacation and had a friend watch my tank and feed. He obviously overfed . I could smell it in the tank when I got back. Not a nice fresh scent. One of my zoa rocks pretty much melted away in a few days, Alll the rest were fine but this one just had a very negative reaction to the water quality deteriorating. Did a few water changes that week but those zoa's never came back . Must have had about 50 polyps on that rock which I started about 5 months ago from about 6 ..

 

[toky916]

Some do good but then frag swap I bring zoa pox second time.
Then heater broke hit 74 everything was fine half zoa gone ugh start over.