Photograph by Blane Perun


Both Zoanthus and Palythoa have chemicals that are not only toxic to reef inhabitants but also to humans. Palytoxin is the most well and has been documented extensively. It is the most poisonous marine toxin that is currently known. (Mereish et al, 1991).This toxin can potentially cause death and have affect on the nerves, muscles, and the heart. Some victims will even be paralyzed. Because of this when you work with zoanthus you will need to be prepared in advance. Some people handle the zoanthus with their bare hands while others choose to use gloves. Whatever you choose, be sure to follow the zoanthus handling tips below to ensure you don’t get sick.


Since there is a danger with zoanthus you will never want to handle it or even the palythoa if you have a wound that is open. You will want to avoid touching your eyes, mouth, or even nose without washing your hands after touching the species. It is of critical importance to remember this when propagating the species. Even a very small amount of the toxin can cause you to go to the hospital so you must take extra care.


In general, zoanthus are peaceful and their growth rate may be slowed by controlling the load of nutrients provided. However, in some cases they can be aggressive towards soft and stony corals.

Toxin Reality

It may sound scary when you read about the toxin, however don’t let it scare you. I have worked with thousands of zoanthus since the mid ‘90s and only one time had a small experience that caused some nausea and numbness. As the specimen grows you will be more likely to see aggression. This is important to watch out for and something that you might find amazing as it occurs.


It is also amazing that the less color the zoanthus has the faster it will grow. Photosynthesis and absorption are the methods of feeding for zoanthus so the more nutrients and light you have the faster the zoanthus will grow. This can be dangerous when you have to prune the colony through propagation. That is because the toxin is released in a small system rather than a big ocean with currents. Keep this in mind when you are growing zoanthus so you will always know what to expect and how to handle the zoanthus in your aquarium.

Blane Perun

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Whale in Ocean