This investigation examined the effect of varying feed ratios on cultured seahorse (Hippocampus abdominalis) growth and survival using frozen mysids (Amblyops kempii) at daily feed rations of 5, 10, 15 or 20% wet body weight. Feeding these different feed rations did not result in any significant difference in seahorse standard length after 3 months. However, seahorses fed the 10-20% rations were heavier and with higher condition factor (CF). Based on the total amount of frozen mysids offered to the seahorses, the food conversion ratio (FCR) became less efficient with increasing feed ration. However, when the actual mysid consumption was factored in there were no significant differences in FCR. There was a significant difference in daily specific growth rate (SGR), with the 5% ration having the lowest SGR. On a cost/benefit basis, based on the total amount of mysids offered the most cost effective ration for daily length and weight increase was the 5% ration. With actual mysid consumption taken into account, cost/benefit value favoured the 5 and 10% feed rations. Survival was 100% across all treatments. Based on this, a feed ration of 5-10% wet body weight per day of frozen mysids is recommended for cultured H. abdominalis.