The Crown of Thorns Sea Star… what can you say, other than this animal can best be portrayed as terror on legs. Acanthaster Planci, or Crown of Thorns star is a large nocturnal predator, that feeds on coral polyps, and lots of them. Endemic to the Red Sea, Pacific and Indian Oceans, the Crown of Thorns is the second largest species of Sea Star which can attain the size of a dinner plate. Only the Giant Sunstar is bigger than a Crown of Thorns Star. Though many species of Crown of Thorns can be brilliantly colored in magenta, purple, red, orange, green and yellow, this multiple legged(16 or so) Echinoderm is fearless invertebrate.
Laced with venomous spines, hence its namesake, the Crown of Thorns Sea Star contains a neurotoxin that is released through its spines. These spines are very sharp and able to penetrate through wet suits. The handling of a Crown of Thorns Sea Star should not be commonplace. Once stung by a Crown of Thorns Star, you will succumb to a sharp stinging pain that may last for hours as well as the possibility of vomiting and nausea. A blue coloration and swelling around the skin tissue at the site of the envenomation is standard for this serious incident. As with Sea Urchins, car must be taken after getting stung, to make sure that the spine doesn’t break off in your skin. This could further compound problems as infection can set in, plus the potential exists that more venom could enter your body.
A solitary hunter which normally feeds alone without the presence of other Crowns. They feed by extracting their stomach from inside their body into the soft coral tissue, where they release digestive enzymes to breakdown the coral polyps. Crowns will also prey upon brittle sea stars to which the same process is carried out. Such a destructive presence, the Crown of Thorns can decimate feet upon feet of delicate coral polyps over the course of a year. If food becomes scarce, a Crown of thorns is able to live off of its stored reserves for up to six months without having to seek other nutritional means.
The destruction created by these Acanthaster stars is immense and detrimental for reefs where they Crowns forage for food. What, often times, takes years to produce as far as coral growth can be reversed in just hours. With the extra burden placed upon the coral reefs in the form of human carelessness and environmental impacts, coral reefs do not need this added burden.
Measures have been taken to try to reduce the areas that are hardest hit by the wrath of the Crown of Thorns Star, but to no ado, in fact the procedure in the past actually returned full circle and created more of a problem for corals. It was assumed that if people were to chop up the stars, it would kill them. However, just the opposite occurred and it actually created more Crowns. Each cut up part of the star reproduced and formed a new crown of Thorns Star, so if you chopped it up in six parts, you now had six new Crown of Thorns Sea Stars. So this tactic failed miserably, hence this was never applied again. The Triton and Harlequin Shrimp remain the only real threat in reducing the population of the Crown Star. Unfortunately the Triton(mollusk) population has been decimated due to over harvesting by people looking to add a beautiful curio centerpiece in the form of their unique shell. Their is a new study on the table now that is in the introductory stage in trying to reverse the damage created by the stars. It is hoped that by taking the stomach acid and enzymes form the stomach of the Crown and placing it into the leg parts of other Crowns to help to kill these animals. A more substantial scenario is carried out with the injection of sodium bisulphate into the Crown of Thorns Star with good luck. Apparently, there is a species of coral known as Pseudocorynactis, that has been seen consuming the Crown of Thorns stars.
Unfortunately their isn’t any form of quick fix for extracting and reducing the population of these terrors. With the coral reefs already under the gun, they don’t need the graphic violence that is provided by these stars as yet another form of destruction.
As for housing a Crown of Thorns in a saltwater aquarium setting, it has been done, though with the large size attainable, venomous spines, and the specialized foods required by this star to maintain them, it is best to try to find ways of depleting their numbers, instead of keeping these predators alive.
Maybe some studies can be performed on these animals to extract digestive enzymes, venom or other parts of the star for medical purposes as has been done with Horseshoe crabs for example. However, for now the true test of time is, trying to reduce the numbers of these predators before the corals are a thing of the past and become extinct, like so many other life forms preceding them.