So why should you NOT buy a blue-ringed octopus?

<< Cephalopod Articles | | By , University of California at Berkeley

Blue ringed octopus will kill you dead

My primary reason for writing this article is to convince you not to purchase and attempt to keep blue-ringed octopuses in your home aquaria. They are small, exotic, incredibly beautiful animals that are relatively inexpensive (typically around $30) and easy to obtain. I was told by an importer last spring that just one supplier in Indonesia was listing 300 H. lunulata on hand. It seems as difficult for the hobbyist encountering a blue-ring in the local fish emporium to resist buying one as it is for a beachcomber in southern Australia not pick up a cute little octopus seductively pulsing its iridescent blue rings. Each year, thousands of blue-rings are imported into the United States and Europe and find their way into home aquaria.

There are many reasons why I feel blue-ringed octopuses are not appropriate for the home aquarium. First, they are actually expensive for what you get - a small octopus that will probably live at most a few weeks. H. lunulata, the most commonly available species, is not a particularly hardy animal and doesn't do well in shipment. Also, some are undoubtedly collected using cyanide or other poisons and die just days after purchase. Finally, since they have a short natural life span and are collected and sold as adults, they just don't have much time before natural senescence.

Secondly, by buying one, or more likely several, because they keep dying, you are encouraging the collection of an animal that is relatively rare over much of its range. Even with moderate demand, given considerable wastage in collection and shipment, the numbers taken soon may place undue pressure on these animals. Couple this with rampant environmental degradation of the inshore habitats in which blue-rings occur, and we must be concerned about the conservation of these octopuses.

Finally, and most significantly, THESE ANIMALS CAN KILL YOU! And more importantly, even if you are knowledgeable of the risk and take all the necessary precautions, if they don't kill you, they could kill your daughter, grandson, or the neighbor kid down the street. Inquiring hands get into tanks, and octopuses get out of tanks. An octopus will push through the smallest crack to escape, so a typical aquarium canopy will not contain them. Even with "escape-proof" tanks that we have designed specifically for small octopus, they can and do get out. A major concern in our laboratory is that a blue-ring will escape onto the floor and someone unfamiliar with the danger will take pity on it and pick it up using bare hands. Another risk stems from the fact that a blue-ring will crawl into the tiniest nook or cranny in a tank and remain there for days. More than once, even after the most thorough search, I have concluded that an animal had escaped, only to have it reappear, sometimes in my hands, while I was breaking down the tank.

There is too great a risk of someone dying to warrant keeping these animals just so you can have the prettiest, most deadly octopus on the block. I was lucky once and avoided tragedy at the arms of a blue-ringed octopus. Please learn from my experience and pass on buying one next time you see a blue-ringed octopus for sale.

Bibliography/Further Reading

Cheng, M.W. and R. L. Caldwell. 1999. Sex determination and mating in the blue-ringed octopus, Hapalochlaena lunulata. Anim. Behav. (In press).
Hanlon, Roger T. and John B. Messenger. 1996. Cephalopod Behaviour. Cambridge University Press, Cambridge. 232 pp.
Light, William. 1998. Eye of Newt, skin of toad, bile of pufferfish. California Wild, 51:8-14, 49.
Norman, M. D. and M. J. Sweeney. 1997. The shallow-water octopuses (Cephalopoda: Octopodidae) of the Philippines. Invert. Tax. 11:89-140.
Overath, H. and S. von Boletzky. 1974. Laboratory observations on spawning and embryonic development of a blue-ringed octopus. Mar. Biol. 27:333-337.
Roper, Clyde and F. G. Hochberg. 1988. Behavior and systematics of cephalopods from Lizard Island, Australia, based on color and body patterns. Malacologia 29:153-193.
Stranks, Timothy N. 1998. The systematic and nomenclatural status of the Octopodinae described from Australia (Mollusca: Cephalopoda). In: Systematics and Biogeography of Cephalopods, Vol. II. Ed. by Voss, Nancy, Michael Vecchione, Ronald Toll and Michael Sweeney. Smithsonian Contributions to Zoology: Number 586, 529-548.
Toll, Ronald. 1998. The Systematic and Nomenclatural Status of the Octopodinae Described from the Indian Ocean (Excluding Australia) and the Red Sea. In: Systematics and Biogeography of Cephalopods, Vol. II. Ed. by Voss, Nancy, Michael Vecchione, Ronald Toll and Michael Sweeney. Smithsonian Contributions to Zoology: Number 586, 475-488.
Toll, Ronald and Gilbert Voss. 1998. The Systematic and Nomenclatural Status of the Octopodinae Described from the West Pacific Region. In: Systematics and Biogeography of Cephalopods, Vol. II. Ed. by Voss, Nancy, Michael Vecchione, Ronald Toll and Michael Sweeney. Smithsonian Contributions to Zoology: Number 586, 489-520.
Tranter, D. J. and O. Augustine. 1973. Observations on the life history of the blue-ringed octopus, Hapalochlaena maculosa. Mar. Biol. 18:115-128.

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