I. The purpose of this study was to determine whether male blennies are attracted to or repulsed by neighboring prior residents. In a previous study of prior residency, I found that the newcomer often was physically attacked and chased. This obscured the question of whether the newcomer initially was attracted to the resident. In the present study, the two animals were separated by a transparent, perforated barrier so that physical contact was impossible. The newcomer could choose between approaching the resident and utilizing the enclosure within his view or withdrawing and using an enclosure out of sight of the resident. 2. A second variable, that of the effect of prior social experience, was also tested. The newcomers were separated into two classes depending on whether they dominated or were subordinate in previous social encounters. The effects of these two variables were separated by means of a 2 X 2 factorial design. Four measures of approach/ withdrawal to the prior resident and three measures of enclosure choice were employed. 3. Those newcomers that had dominated in previous encounters approached the prior resident. They did not demonstrate a preference for either of the enclosures during the observation period (30 minutes). A measure covering a longer period did reveal a preference for the enclosure near the resident. 4. The subordinate fish neither approached nor avoided the resident. They did use the enclosure farther away from the prior resident more than they used the other enclosure, hower.