Morphologic observation on embryonic and larval development of Amphiprion frenatus

【Objective】Observed and recorded the embryonic development and early ontogenesis of Amphiprion frenatus from fertilization to hatching，to provide scientific basis for artificial breeding of anemonefish.【Method】Artificial seawater was used for aquaculture，anemonefish spawned at（27±1）℃，and in the salinity of 27‰ conditions. Artificially hatching and breeding larval and juvenile after the aquaculture water was sterilized by ultraviolet lamp. Morphological changes of zygote and larval and juvenile during development were observed regularly under a microscope and the images were freehand sketched.【Result】The fertilized eggs of A. frenatus were long strips，orange-red or pink，with a gourd-like oval shape in outline，with a long diameter of 2.40-2.60 mm and a short diameter of 0.90-1.20 mm. According to the division，differentiation and developmental morphology of the zygote，the embryonic development of A. frenatus could be divided into following stages：precleavage stage，cleavage stage，blastocyst stage，gastrum stage，neuroembryo stage，segmental stage，turnover stage，angiogenesis stage and organogenesis stage. It took 8-10 days for the zygote to develop and break its egg membrane. The length of the newly hatched A. frenatus was 4.10-4.50 mm. On the first day after hatching， they could open their mouths to take food. They took about 7 d to develop from larva stage to juvenile stage. The caudal， anal and dorsal fins were separated from each other and the body length at this time reached 7.67±0.48 mm. The first white stripe appeared on the 20 d after incubation. On the 30 d after hatching，the body color of juvenile fish changed from black to dark red and began to grow a second white stripe. From 50 d after hatching，the second white stripe began to fade. On the 60 d after incubation，its body color began to turn red.【Conclusion】The actual development time of the embryo body is 8-10 d，which is longer than that of other species belonging to Amphiprion. The reason is that the fertilized eggs of the A. frenatus are larger in size. In addition，the incubation environment temperature has influence on the development time of fertilized eggs，and the higher the ambient temperature is，the faster fertilized eggs of A. frenatus develop. The feeding of larval and juvenile of A. frenatus can be divided into three stages by feeding different types of bait to ensure the high survival rate of larval and juvenile.