Significant Increase in Survival of Captive‐bred Juvenile Banggai Cardinalfish Pterapogon kauderni with an Essential Fatty Acid‐Enriched Diet

Abstract Pterapogon kauderni is an endemic, direct developing, coral reef fish from Indonesia, which has become very popular in the aquarium community. During development of a captive breeding program, high frequency of shock syndrome events and associated mortality was observed in juveniles fed a diet of newly hatched Anemia. After about a week post‐release, juveniles became extremely sensitive to external stimuli, such as feeding and turning the lights on. A series of five tests (mean duration = 116 d) were conducted to investigate a possible dietary essential fatty acid deficiency. A significant increase in survival ( P < 0.001) and decrease in frequency of shock syndrome events ( P < 0.05) were observed in juveniles fed a highly unsaturated fatty acid‐enriched diet. Juveniles fed the un‐enriched diet suffered a mean of 1.4 events/ individual, whereas those fed the enriched diet had a significantly lower mean of 0.08 ( P < 0.001). Mean mortality (all tests) for juveniles fed the un‐enriched diet was 80.7%. whereas it was 5.3% for those fed the enriched diet. No individual fed the enriched diet died after suffering a shock event, whereas in four out of five tests several individuals (mean = 2.26) fed the un‐enriched diet died a few minutes after the event. No event was observed during the first week after juvenile release: the mean days at which the first event occurred (all tests) were 26.8 (un‐enriched) and 26 (enriched). and the mean week at which the highest frequency of shock events occurred was 4.7 (un‐enriched). The results of this study have particular significance for conservation because of the threatened status of P. kauderni.