Embryonic development of Angel fish (Pterophyllum scalare)

Abstract

The aim of this study was to describe the sequence of the ontogenetic process in Pterophyllum scalare and the time required (hours-degrees) for the development of morphophysiological events. The eggs used for this purpose were obtained from natural breeding angelfish (P. scalare) derived from brood stock. Samples of eggs were arranged on glass slides and observed under an optical microscope for characterization and identification of embryonic stage, the number of cell divisions and appearance of structures in the eggs. These observations were performed every half hour during the embryonic period and then every hour until hatching. P. scalare eggs presented in their entirety lipid droplets. The eggs have adhesive properties and an ovoid yellow coloration when fertilized as opposed to milky white when not fertilized. The standard segmentation observed in embryos of P. scalare was of the meroblástico type, and all stages of ontogeny were verified. Hatching occurred 42.5 h post-fertilization, when the incubation temperature was 28°C. The larva, upon hatching, has anus and mouth closed. The yolk reserve is large in newly hatched larvae. In conclusion, the embryonic development of P. scalare is similar to that observed in other species of the family Ciclidae.