Promotion Of A Model Fish Rosy Barb (Puntius Conchonius): Embryogenesis, Effect Of Salinity On Early Development And Histopathological Toxicity To CCl₄.

Development of a single celled fertilized egg to a multi-celled, fully differentiated organism has always been a subject of endless information and mystery since centuries. The morphological and physiological changes, which occur in the process of development, are very complex, especially in higher living beings. Inspite of this, the fundamental organization of most vertebrates is generally homologous, making it possible to understand the morphological, physiological and genetic mechanisms in a slower breeding higher organism, including humans via studying some small and rapidly breeding organism. In this work we have focused on various aspects of embryogenesis, effect of salinity on early development and toxicity to a tropical fish rosy barb (Puntius conchonius), which, we hope, may provide information relevant to other vertebrates.Recently, rosy barb is rapidly becoming a popular model animal for ecotoxicological and biotechnological studies. However, a study on the complete development of rosy barb embryos from fertilization to hatching was surprisingly lacking. We therefore presented for the first time, a detailed table of normal development of the rosy barb embryos from fertilization until post hatching, which is likely to lay a foundation for research in the fields of development biology and biotechnology. Based on embryological staging by morphological criteria, six broad periods of embryogeneis i.e. the zygote, cleavage, blastula, gastrula and larval periods has been defined. These divisions highlight the changing spectrum of major developmental processes taking place during this period. Furthermore, we have examined the process of neurulation and notocord development occurring during the early stages of this fish.