O. joubini is also known as the Small-egg Caribbean Pygmy Octopus. It's mantle is a little under 2 inches long as an adult, with arms to about 3 1/2 inches. In the ocean, it lives on a sandy or mud bottom at less than 30 ft.
The requirements for this little octopus are much the same as for the bimac - a 30 gallon tank would provide a good home. A tank temp of 77 or 78 would be fine.
There are a couple of problems with it - first, they can be reclusive and you may see very little of your octo. Then, the LFSs have a bad record of delivering the species of octo you order. You may not get a joubini, in fact you could get a much larger octopus. And finally, if you do get the pygmy you ordered, it has a short life span, only 6 months.
Thank you for the info! I have tried looking on-line but nobody has the information I need. I knew that they didn't live very long but wasn't sure if that was true or not. By the way, do you of any place that sells this type of octo?