The fish store in town has an octopus with a tentacle length of about two or three inches, and the mantle is about 3/4". When it arrived it was much smaller. It's been in there for about a month and is in a ten gallon tank with three - five seahorses and a cleaner shrimp. I think it's tank raised since it accepts frozen food and theback half of the hood is missing, and the owner just says its an octopus, not any particular species. It has no markings from what I can tell, so does anyone have a guess on what species it is? Thanks again.