POST-EMBRYONIC DEVELOPMENT OF FILEFISH THAMNACONUS MODESTUS

Morphological changes of filefish Thamnaconus modestus in early life stages, including yolk sac larva, pre-flexion larva, post-flexion larva, and juvenile stage, were examined in this study. Fish larvae were cultured in indoor concrete tanks filled with sand-filtered natural seawater (salinity 32—33) at 22—25℃ and light intensity of 1000—2000 lx under constant aeration. Our observed developmental stages can be summarized as the following:the newly hatched larvae relied on yolk nutrition until 3dph (0—2dph, i.e., yolk-sac larvae), the mouth of the larvae opened at 3dph (3— 18dph, i.e., pre-flexion larvae), the tail end of notochord upwarped at 19dph (19—24dph, i.e., flexion larvae), complete tail fin developed at 25dph (25—31dph, post flexion larvae), and all fin rays and scales nearly developed at 32dph when the larvae turned to juvenile stage. After 40dph, the young fish had the same appearance as the adult filefish gradually. In this work, the morphological development of pigment patterns and developmental characteristics of larvae mouth were also described.