P is for Palythoa

Many people like salt water reef tanks for the colorful, active fish, but most hobbyists I know are even more fond of their corals. At least for now, I’m finding myself among them.

Some of the most colorful corals (Cnidarians, to those in the know) are found in order Zoantharia. We’ll revisit genus “Zoantha” in a couple of weeks, but today is “P” and that means Palythoa – a genus within Zoantharia (and family Sphenopidae).

TL;DR: Nuclear Green Palythoas:

Palythoas, or “palys,” are polyp corals that tend to grow taller and larger than other zoanthid polyps (though not always – among cnidarians, diversity abounds). Many palys have fancy names like “Captain America” (photos to come) and the “Nuclear greens” shown above.

They also grow quickly. I bought that 8-polyp cluster a month ago. Not only have the polyps more than doubled in length and diameter, they’ve sprouted five more baby polyps too, and the baby clones don’t stay that way for long.

Some people think they look like venus flytraps. It’s an apt analogy. Palythoas feed on anything in the water, and will snap shut on pieces of shrimp or other food that float within reach (and digest their meal before reopening).

Like many corals, the palythoa’s appearance says “flower,” and it’s easy to forget these are animals, not plants. But some members of order Zoantharia produce one of the most dangerous toxins in the world. It takes only 8 micrograms of palytoxin (chemical formula C129H223N3O54) to kill an adult human being – and toxic zoanthids can produce 2-3 milligrams per polyp. (Small wonder that smart hobbyists won’t reach into tanks with an open cut.) Not all members of order Zoantharia produce palytoxin, and even the ones that do don’t always produce it in such lethal amounts, but it’s certainly something to remember.

Forget the snake, the scorpion and the pit bull. That “flower” will get you faster than all the others put together.

2 thoughts on “P is for Palythoa

  • April 19, 2011 at 8:10 pm

    Fascinating! I have a friend who keeps a salt tank and like you, he is more in love with the corals than the fish most days. I had no idea some were so deadly toxic!

    • April 20, 2011 at 11:22 am

      Amazing, isn’t it? I didn’t know either until I started keeping them. I love finding out about hobbies (other people’s as well as mine). Thanks so much for stopping by, and tell your friend he’s not alone – the corals are really amazing animals (even if my brain does keep thinking “flower” when I watch them!).

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