There was a species discovered awhile ago that formed colonies and was observed pair bonding, intimate mating and spawning multiple times over their lifetime. Completely unlike other octopuses. The Larger Pacific striped octopus.
Sadly, their lifespan is only about two years, which probably is why they aren't the dominant species.
I can't remember exactly where I learnt about the LPSO. Might have been a documentary. Hopefully climate change doesn't wipe them out.
There is a book by Adrian Tchaikovsky about a planet taken over by genetically modified octopuses that started their own civilisation. They even had their own space ships. Children of Ruin is the title if anyone's interested.