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Longfin batfish Platax teira is one of the most important finfish species in Asian aquaculture. However, knowledge on early ontogeny and reproduction of this species in captivity are scarce and incomplete. In this study, the embryonic, larval and juvenile development of P. teira are described and illustrated for the first time. The effect of temperature (27, 30 and 33 °C) on hatching rate, yolk-sac volume and oil globule volume was demonstrated. Cannibalism control via aeration adjustment for the enhancement of larval survival was also examined. Fertilized eggs were spherical, buoyant and had a diameter of 1.29 ± 0.05 mm (mean ± SD). Embryonic development lasted 16 h at 26.2 °C. Newly hatched larvae were 2.81 ± 0.24 mm in total length ( L T ) with 24 myomeres and had an oil globule in the ventroposterior area of the yolk sac. Early larvae had xanthophores appeared all over the body, except for the tip of the notochord. Larvae completed yolk absorption within 3 days post hatching (dph) at 3.41 ± 0.11 mm L T . Larvae were fed initially on rotifers Brachionus ibericus , followed by Artemia nauplii and finally weaned onto an artificial diet. From 8 dph, the larger larvae (over 4 mm L T ) began to exhibit cannibalistic behaviour. Transformation of larvae to the juvenile stage was completed at 23.80 ± 1.98 mm L T , all fins had the adult complement of rays and spines. A statistical model: Y  = 2.4968e 0.0786 x , where Y is mean L T (mm) and X represents dph, explained 96.45% of variation in growth ( P  < 0.001, R 2  = 0.9645). The hatching rate, yolk-sac volume and oil globule volume of newly hatched larvae were significantly ( P  < 0.05) decreased when the incubation temperature increased. Only 2–6% of embryos hatched at 33 °C, while the hatching rate was 63 ± 6% at 27 °C. Larvae reared in aeration rate of 300 mL min −1 attained the highest survival rate at 70.00 ± 7.20%, but remained significantly ( P  < 0.05) lower in cannibalism: 24.44 ± 4.16% compared with 66.67 ± 5.44% in 20 mL min −1 . These results indicate that the optimal incubation temperature recommended is approximately at 27 °C, and aeration at 300 mL min −1 could enhance larval survival by reducing cannibalism. [ABSTRACT FROM AUTHOR]

Bluestreak cleaner wrasse, Labroides dimidiatus , is one of the top ten most exported fish to the global trade in marine aquarium fish and a key species for reef fish diversity. However, knowledge on reproduction and early ontogeny of this species in captivity are scarce and incomplete. Daily spawning, early development and appropriate rearing condition (temperature and salinity) for the larviculture of L. dimidiatus were studied for the first time. We raised wrasse larvae by using an inorganic fertilization method to produce natural assemblages of phytoplankton and zooplankton, and compared it to the higher N: P ratio group and traditional rotifer-fed group. A single male dominated a harem of three females, spawning between late afternoon and dusk. L. dimidiatus spawned 305 times from 1 May 2011 to 30 April 2012, 86.9 ± 10.1% of which resulted in fertilized eggs. Fecundity ranged from 53 to 25,108 eggs per spawn with average hatching rate of 72.2 ± 22.6%. Fertilized eggs were spherical, buoyant and had a diameter of 0.68 ± 0.02 mm. Embryonic development lasted 19 h at 27.3 °C. Newly hatched larvae were 1.81 ± 0.06 mm in total length (L T) and had an oil globule in the ventroanterior area of the yolk sac. First feeding took places at 3 days post hatch (dph) which is marked by the widening of the gut. At 41 dph, transformation of larvae to the juvenile stage was completed at 12.60 ± 0.98 mm L T. On the scanning electron microscope observations, the fertilized egg membrane was smooth and lack surface sculpturing. The distribution density of pores was 61 pores 100 μm−2. The micropyle was circular or oval-shaped, and the diameter was 6.90–7.13 μm. Several neuromasts were found on the head and body surface of newly hatched larvae. The results showed that unicellular algae, zooplankton within the size ranges of 48–150 μm and larval survival of L. dimidiatus were all significantly (P < 0.05) higher in the fertilized treatment (maintaining the inorganic nitrogen and phosphorus concentrations of 700 μg N L−1 and 100 μg P L−1, respectively) compared with the others. These results indicated that the optimal conditions for embryo incubation and larval rearing of L. dimidiatus were combinations of temperature 27 °C and salinity 33 psu. Our results of this study may provide a keystone for further studies to determine the successful mass-scale production of juvenile L. dimidiatus. [Display omitted] • Y ear-round natural spawning, early development and ultrastructure of Labroides dimidiatus were reported for the first time. • The optimal rearing conditions for the eggs and larvae of L. dimidiatus are recommended to be 27 °C and 33 psu, respectively. • Controlling the amount and ratio of N and P by inorganic fertilization increase the important initial prey for larviculture. • Present results indicate that L. dimidiatus is a potential species for captive-bred marine ornamental fish. [ABSTRACT FROM AUTHOR]