| Upon hatching, the caudal portion of the body gradually straightns out after which the larvae start to swim by using their tails for propulsion. The large head appears to be slightly deflected on account of the fairly large, ovate-elliptical yolk sac. The body appears entirely transparent without any sign of pigmentation. The vent is discernible just a short distance and posterior to the yolk sac. The fully straightened larva measures about 1.1 mm long. The finfold becomes distinctly defined from the middorsal region of the nape toward and around the caudal to the posterior of the yolk sac. The optic vesicles and the fin fold remains entirely free from pigments (Ref. 110258).
After day 1, the larva has grown to about 1.5 mm long. The large and elongated head is no longer deflected on account of the greatly reduced yolk sac. Eyes have become large and prominent. The body across the nape is fairly thick on account of the yolk sac, tapering gently to a long pointed tail. The numerous large somites become very visible from a point just posterior to the primodial pectoral fin to the end of the caudal. The chief characteristic of this stage is the appearance of distinct pigments. Grayish black melanphores become visible across the occiput, on the upper lip, on the anterior and posterior areas of the yolk sac, and about the posterior gut region. A series of melanophores one each on the 20 visible somites, extending from the anal opening toward the tail, becomes also evident. Those melanophores across the occiput, upper lip and along the vent produce pseudopodidalike extensions, connecting one melanophore to another just like a necklace. The primordial pectoral becomes visible at this stage. It appears as a protrusion a short distance posterior to the auditory capsules.
Complete absorption of the yolk occurs on the second day after hatching. |