I usually offer a few different items over the course of the first day or two, and see which gets a good response, and go from there...octos can be picky as to what they want...try a local baitshop for killifish,crawfish (small ones), or shrimp...local saltwater petshops should have ghost shrimp, or in a pinch, feeder fish. Once the little thing gets used to you and the tank, he/she will let you know when its time for dinner by actively crawling about, searching for food. I have never fed more than 5 times per week, but each octo is different, and you have to cater to their whims...which is half of the fun!
Good luck, and let us know how it goes!
I tried several types of food with Tralfaz (frozen shrimp, live shrimp etc.) but he seems to prefer live crayfish. I am able to get them at my LFS on a weekly basis.
I try to feed Tralfaz every other day (I've read that over-feeding octos can reduce lifespan). I started out giving him one small crayfish per feeding. I've no gotten to the point were he eats 2 medium size (5" or so) crayfish. I knew that it was time to up his feedings because he would eat the first crayfish and then start "walking" across the front of the tank eye-balling me.
He seems to be in good health thus far :D . I think that every octo is probably a little bit different and I'm sure that other members may have different feeding schedules for Tralfaz's siblings?? Hope this helps somewhat.
In the aquarium we pretty much feed every day, adjusting food to Mr Henry's apparent appetite. He's a big guy and usually has 2 or 3 large crabs either cancer crabs ( Cancer novaezelandiae) or Paddle Crabs (Ovalipes spp) every day. By large crabs I'm talking between 15 & 25cm carapace width. Our smaller octis (which are more the size you'd want to look after at home (welllllllll p'rhaps it's be more accurate to say the size most could afford tanks to hold at home :D ) get 2 or 3 small (~ 3 or 4 cm carapace width) shore crabs of a variety of spp per day per octi.
Of course we're very lucky in that we can go collect food!
PS the big octi is called Mr Henry, because our senior aquarist has two young daughters who are huge fans of the Wiggles!