The aim of this study was to evaluate the potential use of the harpacticoid copepod Tisbe spp as prey in Hippocampus reidi culture together with the effect of natural (14 L/10D) or prolonged (24 L/0D) photoperiod. After release, the juveniles were divided into four experimental groups as follows: group A (control group) fed rotifers ( Brachionus plicatilis) followed by Artemia nauplii subjected to 14 L/10D photoperiod; group B fed a mixed diet of rotifers and Tisbe spp nauplii followed by a combination of Artemia nauplii and Tisbe spp copepodites/copepods subjected to 14 L/10D photoperiod; group C fed rotifers ( B. plicatilis) followed by Artemia nauplii subjected to 24 L/0D photoperiod and group D fed a mixed diet of rotifers and Tisbe spp nauplii followed by a combination of Artemia nauplii and Tisbe spp copepodites/copepods subjected to constant light. We observed higher survival and better growth performance in juveniles fed a combined diet and subjected to an extended photoperiod respect to those fed a standard diet or exposed to natural photoperiod. In conclusion, we found that the harpacticoid copepod Tisbe spp may be considered a valuable live prey for H. reidi culture when used as a supplement to the traditional diet based on rotifers and Artemia nauplii and that photoperiod may play an important role in the successful culture of this species.