An experimental artificial reef was designed and placed in the Marine Reserve at Tabarca (Alicante, SE Spain) to avoid trawl-fishing activities on the Posidonia oceanica seagrass bed and to provide alternative fishing sites. The fish assemblage monitoring of the experimental artificial reef for 1 year is presented. The number of fish species recorded (21 spp.) is lower than that found for nearby natural rocky bottoms close to the site studied. This difference can be accounted for due to reef characteristics, such as module design, relative low volume submerged, excessive depth and/or high degradation of P. oceanica beds surrounding the experimental artificial reef. Changes in the fish assemblage throughout the study period due to seasonal nature cannot be clearly distinguished from later colonization episodes. The main effect of the experimental artificial reef seems to be the attraction of subadults and adults of demersal fish species from nearby natural rocky bottoms.