Interesting note and I don't know what, if anything, it means but in the photos with the seahorse, there is no dark ring around the eye, in the photos with the block, there is. Jennifer Mather mentions the "eye bar" (line in front of and after the pupil making the eye look straight) in Ceph's new book, Octopus: The Ocean's Intelligent Invertebrate as being a possible sign of being on guard and I have wondered about the darkening around the eye in brieareus (I don't recall them showing the line like the hummelincki but that may be lack of attention/remembering) being the same kind of thing. My guess it would be more you being attentive with food in the tank than the actual toy but it is something to watch and guess about.