The habitats of giant clams are undergoing environmental changes, and giant clam populations are declining. The present study was conducted to facilitate clam conservation. We conducted three 18-week trials to investigate the effects of nutrient, temperature, and salinity on the growth performance and survival rates (SRs) of juvenile Tridacna noae, adult Tridacna crocea, and subadult Tridacna derasa, respectively. Regarding nutrient sources, no significant differences were observed in shell length gain, specific growth rate, or SR between clams fed with Chaetoceros muelleri or commercial feed (hw nanotip) and those in a control group (juvenile phototrophs). Regarding temperature, clams cultivated at 27 °C exhibited significantly better growth performance and SR than did those cultivated at 19 °C or 31 °C (p < 0.05). By week 6, all clams in the 19 °C and 31 °C groups had died, indicating that suboptimal growth temperatures have severe adverse effects. Regarding salinity, clams cultivated at 34‰ exhibited significantly higher length gains and specific growth rates than did those cultivated at 20‰ or 25‰ (p < 0.05). SR was not significantly affected by salinity. Understanding how environmental factors affect giant clam populations may help researchers devise effective clam conservation strategies.

The captive breeding of marine ornamental fish with specialized larval requirements—such as Chaetodontoplus mesoleucus—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 C. mesoleucus 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—Euplotes sp., Brachionus sp., and Bestiolina coreana—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 B. coreana 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 C. mesoleucus 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.

The marine ornamental species trade relies heavily on wild-caught specimens, including the Vermiculated angelfish (Chaetodontoplus mesoleucus). Captive breeding of this species faces challenges with limited detailed knowledge available beyond 2 days post-hatch (dph) regarding the influence of environmental factors. This study provides a detailed characterization of C. mesoleucus from early development to 381 dph. Under controlled laboratory conditions, the effect of temperature (22–37 °C) on hatching rate, deformity rate, hatching period duration, time to 50% hatch, and survival rate is investigated. Additionally, the influence of different salinities (0–38 psu) on hatching rates and larval deformity rates was also examined. The optimal incubation temperatures for high hatching rate and minimal larval deformities are found to be within 25–28 °C. A lower salinity threshold of 10 psu was established for successful hatching, and the optimal salinity range for minimizing larval deformities was 33–36 psu. These findings provide crucial baseline data and practical recommendations for optimizing hatchery protocols for C. mesoleucus, contributing to enhanced larval survival and the potential for sustainable aquaculture production, thereby reducing the pressure on wild populations.