In Tasmania, Australia, commercial seahorse culture takes place in tank systems in which approximately 75% of the water is exchanged daily from the Tamar River estuary. As such, some water conditions such as temperature fluctuate on a daily and seasonal basis. The aim of this study was to examine the effect on growth, condition, survival of, and Artemia ingestion by, early juvenile seahorses, Hippocampus abdominalis, cultured for 6 wk at temperatures within the species' natural range (8-24 C) and above it (26 C). Seahorses cultured at 20 C were longer and heavier than those at 17 C, although not significantly different to 23 C. There were no differences in survival or Artemia ingestion of juveniles cultured at 17, 20, and 23 C. At 26 C, 100% mortality was reached on Day 15. This study demonstrates that H. abdominalis can be reared in captivity at a range of 17-23 C in early life stages without compromising growth and survival.