We finish the A to Z blogging challenge with The Corals That Tried To Kill Me. Most people call them Zoanthids (Order Zoantharia, genus Zoanthus).

Order Zoantharia consists largely of colonial, tentacled polyp corals. Rather than describe their appearance in detail, I’ll do this:

Giant Poseidon Zoas

And this:

Ring of Fire Zoas

Zoanthids produce palytoxin, one of the most toxic natural substances. The lethal dose for an adult human (technically the LD-50, for the chemistry geeks among us) is 8 micrograms. Ironically, the night I first blogged about palytoxin I also handled some corals with an open cut I didn’t know about (let’s hear it for paper cuts) and ended up with classic symptoms of palytoxin poisoning, though I didn’t actually realize it for several hours.

The Zoas That Tried To Do Me In

Pity we’d passed “I” already, but Irony knows no season and no statute of limitations.

At present, I have 15 varieties of zoanthids in my aquarium. They demonstrate a remarkable range of colors, shapes and sizes, which makes them a favorite among aquarium hobbyists. With the exception of trying to assassinate me periodically, they also do very well in my tank, which makes them my favorite too.

Zoanthids are photosynthetic and also consume food from their environment, mostly small meaty foods like shrimp and phytoplankton. Some of the palythoas (which belong to the same order as the smaller zoanthids pictured above) even close up around larger pieces of food, much like venus flytraps.

It looks like this:

And now you know a little about zoanthids.

Thank you to everyone who has stopped by and commented during the A to Z challenge – come back on Monday for a special photographic surprise!

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