Yes, that is indeed an awesome hitchhiker. At first I was smiling to myself as there wasn't a fish in sight in most of your pictures, until I saw those tangs.
Looks like they are cohabitating well together, and if you feed that octopus as much as you are currently, I have to imagine it will grow more rapidly.
Hopefully there are those here with enough experience to give you the adequate feeding schedule so you don't end up with a giant octopus-in-a-box.
Great pictures!
