How big do they grow? Lovely ppics
They are so rubbery it is difficult to measure a live one, so they are usually sized by telling the size of their "mantle", which is the bag that you would think of as their head. When I caught my octopus, a female I named "Lefty", she had a mantle size of about two inches. When she was fully grown her mantle was about 3 3/4 inches, and if she really wanted to, she could probably manage an arm span of about 30 inches. Experienced octopus keepers say that a 50 gallon tank is minimum for a bimac. I agree, but bigger is better.
A few weeks ago I was looking around at low tide and a caught a much larger one, with a mantle about 5" long, and an arm span of probably 4 feet. I'm glad Lefty never got that big. I've heard of some around here that are much larger (6 foot span?). There are two species here, that look almost identical (O. Bimaculatus and O. Bimaculoides (like Lefty)). Bimaculoides lives a little shallower, and tends to be smaller, so the really big ones I've heard about are probably Bimaculatus.
What do you feed him?
Kristina
She gets a small piece (about 4 cc) of thawed frozen shrimp, or scallop every two days. Some octos won't take dead food, but Lefty does, so it is cheap and easy. When I go to the beach at low tide I try to grab a little shore crab for her. Octopus are smart (probably about as smart as a mouse which is brilliant for a mollusk) and they get bored easily, so they like to hunt live food. Plus, the variety improves the diet.