What is a octopus group called?
octopi
Octopi is not incorrect, but is not technically correct either.
Octopi is Latin and is the correct plural of Octopus, but the word
octopus is not Latin. It is a Greek word. And the correct plural of
octopus in Greek is "octopedes". Now the real kicker is that even
though it's a Greek word, any word that is used in the English
language is now an English word. So the Greek or Latin plural is
technically incorrect.
The official, proper pronunciation is -- octopuses.
Source: Merriam-Webster