Preliminary studies on morphology and digestive tract development of tomato clownfish, Amphiprion frenatus under captive condition

The study investigated on the growth, morphology and digestive tract development of Amphiprion frenatus larvae under captivity con dition. A total of 15 larvae were sampled from 1 day after hatching (DAH) to 20 DAH for measurement of total length (TL), head depth (HD), eye diameter (ED), body depth (BD), head length (HL) and standard length (SL). For data analysis, total length (TL) was used as variable with respect to other morphometric characters to plot relative growth curve. The relative growth equation of SL, ED, BD and HD, HL was estab lished by using Regression. A total of 15 larvae were sampled from 1 DAH to 17 DAH for histology procedure. Result showed that A. frenatus hatched at the advance stage with developed and functional eye, mouth and fins. Pectoral fin forms at 3 DAH (5.229 ± 0.17 TL). Notochord flexion occurred at 5 DAH (5.675 ± 0.07 TL). The complement of the notochord was characterized by the orientation of the caudal fin rays at 4 DAH (5.399 ± 0.08 TL). The reddish coloration appeared on 17 DAH (9.7695 ± 0.22 TL). At 20 DAH (13.31 ± 0.83 TL), two white bends were formed and bordered by melanophores along the bend. The total length (TL) has significant relationship with standard length, head length, head depth, body depth and eye diameter. Histology of digestive tract of A. frenatus larvae at 24 hours after hatching showed alimentary tract is evident, with gut and liver differentiated. At 2 days after hatching, a well developed alimentary tract is evident, with distinct stomach, midgut and hindgut. Liver and pancreas are differentiated. On the 5 DAH (5.675 ± 0.07 TL) mouth cavities are well developed. The mouth and pharynx were lined with cubic epithelial cells of irregular shape. It could be concluded that after 8 days incubation, A. frenatus hatched at the advance stage with developed and functional eye, mouth and fins. Relative growth concluded that the total length (TL) has significant relationship with SL, HL, HD, BD and ED. Histology of digestive tract of A. frenatus larvae showed that the A. frenatus larvae have a straight tube closed at the mouth and histological differentiated along its length at newly hatching. It was found also several functional organs such as liver, midgut and stomach at 1 DAH. It was indicated with the appearance of developed and functional digestive tract at first day hatching larvae. Therefore, live foods such as rotifer are suitable to be fed at early larvae after hatching.