“…Larvae at flexion and mid-metamorphosis had an approximate age of 24 and 51 dph, respectively. The sections (10 µm thick) were stained using the haematoxylin and eosin (H&E) method [ 5 ]. Developmental changes in internal organs and tissues such as the heart, brain, stomach, intestine, kidney, swim bladder, gill, eye, vertebral column, liver, and skeletal muscle are obvious during the transition from flexion to mid-metamorphosis.…”