Pictures of destruction

[Joy_42]

I've posted about this in the "new to the hobby" forum, but it was suggested that I try here as well.

Long intro:

I have had three healthy zoanthid colonies start to disappear overnight. There were no white or brown spots, no changes in levels, temperature, flow or even new livestock additions; they'd be open and vibrant one day and the next day polyps would be missing.

It took me a while to get the bright idea to look after the lights went out, and when I did, I found the zoa colonies were crawling with pods of all sizes. After some debate, I added a mandarin fish (which I will gladly supplement pods for in the hopes it could save my zoas right now). After about a week there was no improvement, only more deterioration, and I looked again... The remaining pods are too large for my mandarin's mouth but are definitely chowing down on my polyps.



My questions:

1) Many people have told me repeatedly that pods don't eat healthy zoas. Does anyone have experience to the contrary?

2) Has anyone had this problem and found a good solution?

3) If my zoas are sick, what can I do to figure out what's wrong with them other than a visual check? There are no white or brown spots and no signs of stress until the pods move in.

Any suggestions or guidance would be greatly appreciated!

Also: the tank has been up for one year, this problem started 2-3 weeks ago, Ammonia is 0, Nitrites are 0, Nitrates are barely more than 0 (color chart skips from 0- 5.0, water tests closer to 0), pH 8.2, Salinity 1.024.

Thanks,
Joy