Early Feeding Strategies for the Larviculture of the Vermiculated Angelfish <i>Chaetodontoplus mesoleucus</i>: The Key Role of Copepods.

Abstract

The captive breeding of marine ornamental fish with specialized larval requirements-such as <i>Chaetodontoplus mesoleucus</i>-remains a major bottleneck in aquaculture, largely due to the lack of techniques tailored to their unique morphological and nutritional needs. The global marine ornamental aquaculture market is valued at approximately USD 2.15 billion annually; however, only around 10% of marine ornamental species are currently supplied through captive breeding, highlighting a substantial technological gap. The artificial propagation of <i>C. mesoleucus</i> is particularly challenging due to the species' small mouth gape and high nutritional demands during early development. To address this issue, we evaluated the effects of three live-prey types-<i>Euplotes</i> sp., <i>Brachionus</i> sp., and <i>Bestiolina coreana</i>-as well as a mixed diet containing all three, on larval performance. From 3 days post-hatch, larvae were fed each prey type at equal densities (15-20 individuals/mL), and water quality was carefully maintained to minimize external influences. Survival and total length were assessed at 14 dph. At the end of the trial, the mixed-diet group showed the highest survival rate (36.2 ± 5.6%), whereas larvae fed only <i>B. coreana</i> exhibited the greatest total length (7.4 ± 1.2 mm) and a high metamorphosis rate (97.8%). These findings demonstrate that prey selection significantly influences the early survival and growth in <i>C. mesoleucus</i> larvae and highlight the critical role of copepods in promoting growth performance. However, as larval biomass was not quantified, the findings should be interpreted with caution, and future studies incorporating biomass assessments are needed to draw more conclusive inferences. The successful mass rearing of this species supports the feasibility of captive production to reduce wild harvesting, protect coral-reef biodiversity, and promote sustainable ornamental aquaculture.