Although some people have successfully kept starfish (seastars) in octopus tanks, I would recommend it only in the case of a very small starfish.
Starfish can be problematic to keep under the best of circumstances. The alternatives, serpent stars, can grow large and aggressive. Brittlestars are the best choice for a ceph tank.
If you do keep an octopus with a starfish, make sure that the octopus is considerably larger than the starfish. Can a starfish kill an octopus? We had one incident here with a Tonmo member's octopus where it appeared the starfish trapped and killed the octopus. Later I found references to and a photo of an octopus being eaten by a starfish in the Monterey Bay Aquarium book, Octopus and Squid, by James C. Hunt.
Nancy
Starfish can be problematic to keep under the best of circumstances. The alternatives, serpent stars, can grow large and aggressive. Brittlestars are the best choice for a ceph tank.
If you do keep an octopus with a starfish, make sure that the octopus is considerably larger than the starfish. Can a starfish kill an octopus? We had one incident here with a Tonmo member's octopus where it appeared the starfish trapped and killed the octopus. Later I found references to and a photo of an octopus being eaten by a starfish in the Monterey Bay Aquarium book, Octopus and Squid, by James C. Hunt.
Nancy