Embryonic and larval development stages of three species (characidae) (Gymnocorymbus ternetzi, Hyphessobrycon herbertaxelrodi, hyphessobrycon serpae)

The embryonic and larval development of three tetra species, black skirt tetra (Gymnocorymbus ternetzi), serpae tetra (Hyphessobrycon serpae) and black neon tetra (Hyphessobrycon herbertaxelrodi) were described under controlled laboratory conditions. In addition, major histomorphological changes and the allometric growth patterns during larval development were have been described. The laboratory-reared broodstock, that is aged 1 year old, were spawned. Hatching occurred 20 ? 22 h after spawning for three species. In black skirt tetra, the cleavage was finished in 2 h and the early blastula stage occurred at 2.04 h after spawning. The gastrulation started at 3.20 h and 30 % epiboly was observed at 3.34 h after spawning. 8-somite stage was observed at 08.33 h and embryonic developmental stage was completed at 21 h after spawning. The newly hatched larvae were 1442 ± 14.3 µm in mean total lenght (TL). The mouth opened at 3 DAH. The yolk sac has been totally absorbed and the larvae started to swim actively within 3 ? 4 days. Notochord flexion began 11 DAH. The metamorphosis was completed and the larvae transformed into juveniles at 32 DAH. The results for the other species were similar during embryonic and larval development stages. In this study, the full developmental sequences from egg to juvenile of these tetra fish were described for the first time.