Otcopus for beginners
Just to temper a little what Jean said. My first marine aquarium was an Octo aquarium where I kept a Bimac. Before setting up the aquarium I did all the research (Many thanks to this website and the excellent content", made sure the tank was stable and well cycled, put some damsel fish in for a few months. After I was satisfied with my water quality I put in the Bimac. He lived for 9 months after which "SHE" laid her eggs and died. I considered this a success but with a sad, inevitable outcome. The point is, I did my homework, got second, third, fourth opinions, and had my water tested like crazy by people with lots of experience. BTW damsels are tough as hell, one survived the entire 9 months with the octo without becoming food. I also had a peppermint shrimp that survived the experience none the worse for the wear.