Larval organogenesis in gold gourami (trichopodus trichopterus pallas 1770) histological observations

Abstract

This study informs on the ontogeny of larval development of gold gourami, commercially precious fresh-water aquarium fish. Starting from the newly hatched larvae until the days 36-40 when larval development was completed, the main histological findings of the early stages of the development of gold gourami were presented. Gold gourami larvae were altricial at the hatching time, with an undifferentiated digestive tract and a large yolk sac, which was completely consumed within 7-8 days after hatching (DAH). The mouth opened 3DAH and the digestive tract was differentiated with distinct oesophagus, stomach, midgut and hindgut at 4-5DAH. On the 11-13th days, labyrinth organ specific to the fish species with labyrinth was observed to be formed. It was also found that the digestive tract was completely formed, and the number of intestinal folds increased. On the 15-19th days, swim bladder was seen to grow in total without leaving any lobe. It was observed that the brain was divided into telencephalon, diencephalon, mesencephalon and rhombencephalon parts, respectively. Day days, the formation of the gill lamella and caudal fin development were completed. On the 36-40th days, the larval period ended with the formation of the fin rays. Larval development was completed and reached juvenile stage.