ZoWhat
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Ive been researching if Urchins eat zoas and based on reading there are two camps:
1) urchins will cross over top of zoas in their eating path... the zoas will hide....but once the urchin passes over the zoas return to normal. Zoas are toxic and won't be eaten by urchins.
2) urchins can and do eat zoas, eventually
I'm here to say that it's a mixture of both schools of thought.
Urchins WILL EAT ZOAS if the right circumstances occur:
* if the zoas are relatively non toxic and doesn't have much, if at all, any palytoxin
* if the zoas are already starting to slowly melt or are injured/hiding due to some problem in the tank
* if the urchin is starving for algae and not finding much to scavenge
I personally witnessed a colony of about 10heads of Utter Chaos that were hiding, struggling a little bit due to some unknown water quality change. 4 of the 10 heads were hiding, shriveled.
I saw my pincushion urchin take the opportunity rather quickly to beeline it to that area...(maybe they can smell struggling zoas in the water column)
I watched, off and on, the urchin slowly move over the utter chaos. In about 2 hours once the urchin moved off that area, there was nothing but bare LR. any evidence of utter chaos being there were G.O.N.E. .... all utter chaos tissue was stripped to bare rock. Before the urchin moved in 4 heads were hiding/struggling but when the urchin was gone it ate the 4 struggling heads and the 6 fully extended heads
CONCLUSION:
* I'm CONVINCED urchins do if fact eat zoas if the zoas are struggling/shriveled.
* Urchins are scavengers and will eat algae, meat, coral tissue. They are little garbage trucks eating coral tissue that is wounded/struggling/dying.
* urchins will eat zoas that are low in toxicity
* once they hover over a struggling zoa, expect the whole colony to be probably eaten
1) urchins will cross over top of zoas in their eating path... the zoas will hide....but once the urchin passes over the zoas return to normal. Zoas are toxic and won't be eaten by urchins.
2) urchins can and do eat zoas, eventually
I'm here to say that it's a mixture of both schools of thought.
Urchins WILL EAT ZOAS if the right circumstances occur:
* if the zoas are relatively non toxic and doesn't have much, if at all, any palytoxin
* if the zoas are already starting to slowly melt or are injured/hiding due to some problem in the tank
* if the urchin is starving for algae and not finding much to scavenge
I personally witnessed a colony of about 10heads of Utter Chaos that were hiding, struggling a little bit due to some unknown water quality change. 4 of the 10 heads were hiding, shriveled.
I saw my pincushion urchin take the opportunity rather quickly to beeline it to that area...(maybe they can smell struggling zoas in the water column)
I watched, off and on, the urchin slowly move over the utter chaos. In about 2 hours once the urchin moved off that area, there was nothing but bare LR. any evidence of utter chaos being there were G.O.N.E. .... all utter chaos tissue was stripped to bare rock. Before the urchin moved in 4 heads were hiding/struggling but when the urchin was gone it ate the 4 struggling heads and the 6 fully extended heads
CONCLUSION:
* I'm CONVINCED urchins do if fact eat zoas if the zoas are struggling/shriveled.
* Urchins are scavengers and will eat algae, meat, coral tissue. They are little garbage trucks eating coral tissue that is wounded/struggling/dying.
* urchins will eat zoas that are low in toxicity
* once they hover over a struggling zoa, expect the whole colony to be probably eaten
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