(A, B, F–M, O, and P) lateral view and (C, D, E, and N) dorsal view. (A) 1-cell stage, considered 0 h from fertilization until first cleavage; (B) 2-cell stage, 0,67 hpf; (C) 4-cell stage, 1.33 h; (D) 8-cell stage, 2 h; (E) 16-cell stage, 2.67 h; (F) 32-cell stage, 3.3 h; (G) 64-cell stage, 4 h; (H) 128-cell stage; 4.67 h; (I) oblong stage; 9 h; (J) sphere stage, 15.5 h; (K) 25% epiboly, 17.5 h the embryo is on the right side (arrow); (L) 40% epiboly, 19 h embryo is on the right side (arrow); (M) 90% epiboly, 23.2 h; (N) optic vesicles forming at 90% epiboly stage (arrow); (O) 14-somite stage embryo, at 34 h showing Kupffer’s vesicle (arrowhead); (P) 18 somite stage, 38.3 h, the otic vesicle is apparent (arrow) (Scale—0.5 mm)

(A) Bright field image showing the pigmented cells: dark brown (arrow) and black (arrowhead), (B) the same embryo image under a GFP filter, (C) dsRed filter and (D) merged images showing that only the dark brown pigmented cells are fluorescent in GFP and dsRED filters. Scale—0.5 mm.

(A and C–I) lateral view, (B and I) dorsal view. (A) 40 h 20-somite stage; (B) dorsal view of 20-somite embryo with first pigmented cells appearing; (C) 48 h; (D) 72 hpf; (E and I) 96 h in I the arrow shows the tail tip at the level of the otic vesicle; (F, J and K) 120 h or 5 dpf, in J the spleen is visible only in a dorsal view (arrow), and in K, the tail tip (arrow) passes the otic vesicle (dashed ellipse); (G and L) 144 h or 6 dpf; (H and M) 168 h or 7 dpf; (M) dorsal view of 7 dpf larvae showing the spleen as a red spot (arrow); (N) composition picture of a 8-9 dpf hatching larvae. Scale—0.5 mm. The pictures A, C, D, E, F, G, H and N use the same scale bar.

An asterisk (*) indicates significant statistical difference between the temperatures (ANOVA p < 0.0001)

(A) Hatching rate, in percentage, in mg·L⁻¹. (B) Mortality rate (±Standard Error). (A and B) The graphs correspond to cumulative data. An asterisk (*) indicates significant difference between the values on the corresponding day (ANOVA p < 0.0001).

(A) Hatching rate of live embryos, in percentage, in mg·L⁻¹. (B) Mortality rate of embryos, in percentage (± Standard Error), in mg·L⁻¹. (A and B) the graphs correspond to cumulative data. An asterisk (*) indicates significant difference between the values on the corresponding day (ANOVA p < 0.001).