Zoanthid die off after some tank neglect.

[echoofformless]

I had a ridiculously busy month between work and school and couldn't get to doing a good water change or maintenance on my 29g tank. Finally yesterday I was able to start getting on the ball, and I noticed that my zoas had gotten so thin that I could see a lot of bare rock where they had once been abundant.

All of my other corals did fine through the month - candy cane, finger leather, star polyps, button polyps and mushrooms look perfectly healthy and normal. The stars and buttons have even propogated a bit and moved onto adjacent rocks.

Are zoas that sensitive, or should be keeping an eye on blue legged hermit crabs? I might not assume so, as zoas were fine since June when I added them. It seems they only thinned out during this month of no maintenance. I figure that if someone was eating them they might have been looking ragged right away, yes?

If it is just a question of me keeping up with my water changes and nutrients, will they start coming back now that I'm back in gear? Is there anything in addition that I can do to encourage propagation? Or do you think the culprit are hungry blue legged hermits?

Or what about bristleworms? I've seen some rather large ones on my system at night...

[echoofformless]

No one? Nothing? Really?

[DoctaQ]

hermit crabs and bristleworms dont eat zoas unless theyre already on the way out, other button types along with zoas are generally pretty tough,although often i have zoas that just close up and never open up again, its pretty frustrating

[fsn77]

I would be surprised to see zoas go downhill in only a month. There's certainly some harder to keep zoas that might not appreciate the tank going a month without attention, but the vast majority should have done fine on their own.

While not a direct comparison, about 2 weeks ago I was moving around some of the live rock I have in a vat. I didn't realize it previously, but I had buried a rock covered in zoas under several other pieces of rock several months earlier. To my surprise, the zoas are still alive and must have been feeding on particulates in the water to have survived so long without any light (there was no light over the vat). They were almost completely white from a lack of zooxanthellae (formerly were a nice golden color -- looked like little gold coins), but have already started to color up again as they seem to be regaining zooxanthellae (I moved them back into the light). There's definitely some sensitive zoas, but there's also some really hardy ones, too. It just depends on the particular variety you're keeping.

[echoofformless]

They were called "nuclear zoas" at the LFS. The ones that aren't dead are still opening and behaving normally.

Shall I just hope they come back?

[fsn77]

Unless you suspect some type of zoa disease, I would let them be and hope they recover.