There have been four confirmed deaths from Hapalochlaena bites in the wild. I know of none by blue-rings kept in captivity - unless you count the Vietnamese who cooked some up in a fish stew, ate them and died. Only one of the confirmed deaths was possibly due to H. lunulata, the only species available commercially. I think that case was probably from an undescribed species in northern Australia. In fact, there are no hard data as to whether H. lunulata sold in the US even have lethal amounts of TTX by they time they get to the home aquarium. We assume they do and I am certainly not going to let one bite me to find out, but at this point it is only an assumption.
However, I still would not recommend anyone keeping one as a pet. Generally they are timid and don't move around much, but I have had them lung at a feeding stick and crawl up it almost reaching my hand before I dropped. I have also had them escape. My concern is not that an experience aquarium keeper is going to be bitten, but that someone who does not know about them will get into a dangerous situation. It is pretty easy for an 8 year old to reach into a tank when no one is around and try to touch it. Of course you would keep a poisonous snake in a locked cage, but would the aquarium also be locked. What if one gets out and a child finds it and tries to put it back? These are all scenarios that are very unlikely, but they could happen and have to be guarded against.
As for keeping one for a long period of time, it won't happen. Almost all of the blue-rings sold are fully adult and will scenesce in a month or two. I have keep literally hundreds of blue-rings and the longest I have had an adult last in the lab is about 4 months. If you could find a juvenile, that could be stretched to 6 months, maybe a bit more depending on temperature and diet.
I enjoy working with blue-rings. Their aggressive and reproductive behavior is interesting and they are great to photograph, but there is a down side. I have to keep the lab locked and only allow pairs of people to work with them. We haven't had janitorial service for years. The paperwork brought on because we keep a "toxin" on the Patriot Act list is a pain. Building and maintaining individual secure aquaria is time consuming. Etc. I study them because the evolution of the acquisition and use of the toxin is biological interesting. Would I have one at home in an aquarium - no.
Roy
