Trevor 05/07/03

The sea is a foreign environment. Creatures in the sea have evolved separately from humans for millions of years. Because of this, there are many novel chemicals that are beginning to be discovered in the ocean. There are many corals that produce toxins that are being looked at for medical use. GARF has even participated in this research, donating captive-grown Sarcophytons to the medical sciences, with the hope of finding new treatments for diseases.

However, there is a flip-side to these chemicals. Their effects on the human body are not known. Now, this is not a problem for the average person who never comes into contact with anything from the ocean. The hobbyist on the other hand, should definitely be aware of the possibility of health problems from toxins produced in coral.


Some corals with known toxic properties include Palythoa, Sarcophyton, mushrooms and green stars. Palythoa is by far the most deadly; a species of wild Palythoa .Palythoa has the capability to kill a rabbit after an injection of only 25 nanograms. A toxic dose for humans would be about 4 micrograms. In fact, palytoxin is considered the most toxic organic poison known to humankind.

Symptoms of palythoa poisoning are well-described, due to their unique position as the world’ s most powerful poison: chest-pains, difficulty breathing, racing pulse and low-blood pressure. Death occurs within minutes, and there is no treatment.


While Palythoa, are commonly found in aquariums, the species that produces it is found only sporadically in the wild and is not likely to be in the aquarium. Still, with the world’s most powerful toxin potentially in your living room, it pays to be cautious.

There are also several reported deaths from Rhodactis, a mushroom coral, namely from ingestion by children. However, any coral can potentiallydangerous toxins, and the real danger is in coming into contact with an unknown poison, one that medical science is unable to treat, one that your doctor probably wouldn't even be able to diagnose. The chances of a hospital being familiar with the symptoms of coral poisoning in an inland place are very low.


There are a few easy precautions to take. When cutting soft corals wear eye-protection and gloves. Most soft corals have evolved the ability to squirt their internal juices at an attacker, and somehow they seem to have the ability to aim for the mouth and eyes of the propagator. Everyone at GARF has stories of being sprayed by mushrooms or Palythoa in the eyes and having trouble seeing and intense pain for days.

Gloves are important because the internal liquids from corals are often water-soluble, and can seep into little cuts on the hand. With very toxic corals, mere exposure without any cuts can cause an itchy rash. Also, nearly all corals do better when propagated with gloves rather than being exposed to the oils


of the bare hand. It is best to discard the water that a coral has been propagated in down a drain rather than back in the aquarium. Here is a link to a story by Sally Jo describing the damage a cut palythoa wreaked in her tank:

Of course, those tips apply only to aquarists who regularly propagate their corals. The average hobbyist should be careful when siphoning water from the tank, and be prepared to present the idea of coral poisoning to his or her doctor should an undiagnosable medical condition arise. Children who are likely to put foreign objects in their mouths should also be kept out of the marine aquarium. Most of all, be aware that those marvelous corals in your tank are more than pretty decorations.

They are fierce creatures that have evolved for millions of years in a highly competitive environment- treat your corals with respect!