Which is correct?
Which is the most common and natural for English speakers?
what animal do you like?
I like octopus
I like octopuses
I like octopi
Both octopuses and octopi are acceptable plural forms for octopus.
Personally, and this is just my preference, if you say you like octopus, I think you like the taste of it. If you say you like octopi, I would have to stop and think what kind of pie that was...and then realize you are just being erudite.
So my preference would be octopus for the main dish, and octopuses as pets.