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We haven't done a care sheet for briareus, but many of the guidelines for octos will apply. This is a tropical octopus and needs a warmer tank, maybe 78 degrees, and has long arms. I'd think a 75 gallon tank with live rock would make a nice home. Briareus has webbing between its arms and will enclose a rock to find out what's edible there. It will eat amphipods, crabs, shrimp - the usual octo food.
Briareus lays large eggs and you have a chance of raising the young ones.