Inside out Zoas


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Manhattan Reefs
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64   0   0 for the past few days i've noticed one of my mini zoa colonies opening up but instead of looking like a "saucer" shape .... it looks like a mushroom where the polyp opens up so much it flips the sides down and resemebles the top of a mushroom

What would cause this?

Is this a normal thing?

I've had these zoas for a solid year and never seen them do this.

Water parameters are fine with the exception of my alk which I can never keep a stable number

ALL other corals look fine ... it's only this one mini colony.



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Barnum Island
In my experience zoas that look like little umbrellas are telling you they are getting too much light..move them to a lower location or into an area of indirect lighting (not shade). It will take a few weeks for them to get their original shape back again.

On the other hand zoas that reach up - their 'stalk' becomes unusually long need to have more light.

I've also found that different colored zoanthids are partial to different lighting levels - blues can't take a large amount of light but many pink ones can and they will tend to reach up if you don't put them high enough.
One last thing...when you are moving zoas up - only move them by a few (like 3) inches at a time to see how they do when trying to find their sweet spot for lighting :)

Regarding your alk issue - you really need to try and keep that stabilized - it is probably the most important of the 3 parameters we should be checking in our tanks!
Do you dose?
Do you know what your Magnesium level is?
How long has the tank been up?