Is my Wall Hammer Coral expelling zooxanthellae?

[Aprod]

Hi R2R,

Snapped some photos last night of my wall hammer coral expelling a stringy clearish-brown substance. At first I figured it was standard excretions, but after reading some threads I am not so sure anymore. This happened one day after my weekly 20% water change. The polyps retracted to half the size and the stringy substance kept growing until it separated completely. If it is expelling zooxanthellae, how can I make the coral more comfortable? It appeared to be in a good flow position and is currently on the sand bed, so I doubt it is too close to the light.

 

[James M]

Most likely poop

 

[rkpetersen]

Looks like zooxanthellae to me. I'd be thinking about any recent change in lighting or nutrient levels. Recent sizable water change could be a stressor too. OTOH sometimes a bit of algae being expelled is just a minor adjustment.

 

[Aprod]

Looks like zooxanthellae to me. I'd be thinking about any recent change in lighting or nutrient levels. Recent sizable water change could be a stressor too. OTOH sometimes a bit of algae being expelled is just a minor adjustment.

Appreciate the response! Nitrates (<10 ppm) and phosphates (0 ppm) are very low in my tank, and it is still very young (just over a month old). I think my salinity levels may have jumped a bit with the water change, which could have done it.

I will keep an eye on the coral, but it appeared to be fine last night.

 

[Scotty Buttons]

Did the coral lose any color after that happened? Kind of hard to tell from the pic, but those might be sweeper tentacles.

 

[Geebs19]

This happened to mine when I tried to target feed mine reef roids, I dont feed them anymore.

 

[rkpetersen]

Appreciate the response! Nitrates (<10 ppm) and phosphates (0 ppm) are very low in my tank, and it is still very young (just over a month old). I think my salinity levels may have jumped a bit with the water change, which could have done it.

I will keep an eye on the coral, but it appeared to be fine last night.

Very low nutrients, esp 0 phosphate, can do it. Basically the entire zooxanthellae population that it has can no longer be supported, so it expels the excess. If the situation persists or worsens, all the algae can wind up being expelled and the coral or nem will bleach, after which it may or may not recover.