zoas have weird symptoms , could be a disease?

[fishfree]

hi guys,

I have been keeping zoas for 2 years, and recently found two colonies have some problem, the zoas in the photo (colony up in the middle of the photo) gradually shrink like in the video.

there is no pests, all the other colony is growing fine, anyone has some ideas why?

first, the tentacles gradually become very short and small, and the disc part gets smaller and smaller too, and now they dont close, neither do they stretch and open up , just like the state in the video 24 hours a day, no response to my water blow.

I have more than 40 colonies and only 3 got this problem, all the rest is doing well and some even reproduce very fast.
so I'm lost why this is happening.

checked the water parameter, No3 around 4, Po4 is also fine, in fact, I kept LPS in the same tank and they are all doing great.

if someone know what is wrong with this situation, please shed some light on me, very thanks!

 

[vetteguy53081]

Any changes in lighting or water flow?
Also assure salinity and temperature not elevated
They require iodide as well as strontium in their water
Check under the plugs for any bugs also

 

[littlebigreef]

Once a collection gets past a certain threshold its not unusual for bacterial/protozoan issues to manifest themselves, especially if you are continuing to add to your collection. This may take the form of color shifting, spitting the guts out, the 'shrivel,' skirts burning off, splotchy dark patches on the colony (to name a few).

In your case it seems like you're getting the 'slow fade' where they're reducing down to nothing? I've experienced this my fair share of times. From my experience this is usually indicative of sustained periods under higher par. Specifically, most zoas can tolerate a wide range of par. However, after a period of some time -say 2-3 months- the coral will shrink in size and ultimately fail. It's useful to know what strain you're working with as ALL ZOAS ARE NOT CREATED EQUAL. The vast majority of my collection is between 80-140 par with most of those falling between 110-130.

If your other parameters are in the sweet spot (and you haven't already) I would rent a par meter just to see where you're at. Can you also share the names of some of the strains that are giving you trouble?

I would start here. As someone with a few hundred strains I'll tell you I always have 5 strains that are rebounding, 5 that are failing and a few that are stalled. As for bacterial/protozoan issues that comes with the territory of having a larger collection so IDing (because time is of the essence) and treatment plans are a secondary conversion worth having.