Table 1.

Developmental Stages in the Zebrafish Embryo as Described by Kimmel et al. (1995)

Hours Post Fertilization (hpf)
28.5 °C	25 °C	Embryo Stage	Description
10	12.4	Bud	Head and tail are distinct
12	14.9	6-somite	Optic primoridium notable, Neural keel formation
14	17.4	10-somite	Rudimentary pronephros
16	19.9	14-somite	Brain subdivisions are distinguishable
19	23.6	21-somite	Angioblasts coalesce at midline to form major vessels
22	27.3	26-somite	Blood island cells differentiate
24	29.8	Prim-5	Heart beats, circulation begins
30	37.3	Prim-15	Primary vessels are patent, CCV is broad across yolk
36	44.7	Prim-25	Brain and trunk vascularization begins
42	52.2	High-pec	Liver primordial, Atrium/Ventricle are distinct in heart
48	59.6	Long-pec	Brain microvasculature is patent, CCV less prominent
60	74.5	Pec fin	Retina fully pigmented, hatching gland prominent
72	89.4	Protruding mouth	All ISVs are patent, circulation through gills begins
96	119.3	Hatch	Free of chorion, limited movement