Fungia mucus observation


New member
Hello all, had a rather curious observation during my coral feeding session last night, and have failed to find any real info regarding what may have happened. After feeding my corals the usual mix of foods (reef roids/Cyclopeze/oyster eggs/mysis and brine shrimp mix) I saw a previously undetected xanthid crab come darting out of the rock work and towards a fungia that was about halfway through swallowing a cluster of food. The crab grabbed a bit of food that was covered in the fungias digestive mucus and then (I'm assuming it may have instantly started to eat the stolen food) within seconds had a rather violent looking muscular spasm and died right there on top of the fungia.

Now I'm assuming the mucus was toxic enough to kill the crab if ingested but was surprised at the lack of similar reports after a bit of searching which leads me to think that it may have been some other mechanism, stinging via tentacles perhaps? I was under the impression initially that the digestive system of xanthids was more than capable of handling such toxicity but now I'm clueless. Any ideas?