Hmm, 2 hours and no attempts by anyone else. So let me break my decision not to post the answer.
I am an octopus.
I am an animal that lives in the ocean
Octopi live in the oceans
I move very fast using a strange kind of motion.
Octopi propel themselves using a stream of water ejected at speed
You will never see me in any one group
Octopi don't move in groups, they swim independently. They only hook up when, erm, hooking up! (I needed Wikipedia to confirm this)
Poem written by...Anatomic Soup
The poet's name is a anagram for the answer: I am an octopus.