A team at the Woods Hole Marine Biology Laboratory have developed techniques to keep and breed Octopus chierchiae, a very small octopus species, and they suggest that it may be useful as a laboratory animal. It seems that a female of this species can produce several clutches of eggs during its life, unlike larger octopus species which only produce one clutch. Unfortunately it is probably too small to make a good zoo animal. There is a report at https://phys.org/news/2021-12-team-culturing-pygmy-zebra-octopus.html which has a link to a more technical paper, if anyone is interested.