You might want to try searching Cephbase - they have an image database that might help narrow down the options. Do you have any idea where the octopus originated? http://www.cephbase.utmb.edu/imgdb/imgdb.cfm
I assume if came from Florida. It looks like a large O. mercatoris. At this size, it won't last more than a couple of months before it lays eggs (if a female) or scenesces.
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