Fig. 1

The diet transformation process of S. nematoptera"

Fig. 2

The mating behavior and oral incubation of S. nematoptera. (a) Male (left) puffs out jaws in response to female; (b) the male (right) and the female are swimming side by side in one corner of the tank (as shown by the arrow); (c) female (left) laying egg mass; (d) male (right) turns around and takes the egg mass into mouth (as shown by the arrow)"

Tab. 1

Spawning of S. nematoptera during March to May 2021"

Fig. 3

The egg mass of S. nematoptera"

Tab. 2

Embryonic development of S. nematoptera"

Fig. 4

Embryonic development of S. nematoptera"

Fig.5

Photomicrographs and photographs of the various stages of development of S. nematopter. (a) Newly hatched larvae were (2.82±0.12) mm in total length, with strong phototropism; (b) 1 DPH larvae with transparent bodies ready for feeding; (c) 2 DPH larvae were (3.54±0.23) mm in total length, and most of the yolk-sac was consumed; (d) 4 DPH larvae with a mouth cleft height of (0.23±0.02) mm and a large amount of prey visible in the stomach; (e) 12 DPH larvae were (4.42±0.38) mm in total length, with marked pigmentation on the abdomen and head; (f) 18 DPH larvae with broadened bodies and the presence of dorsal and anal fin flippers; (g) 24 DPH juvenile with morphology approximating that of adult, with the dorsal fin divided into 2 and scales beginning to appear; (h) 50 DPH juvenile with fully formed scales and the same body shape and body markings as the adult; (i) 200 DPH young fish with immature gonads; (j) 360 DPH sexually mature female, (53.13±2.11) mm in total length, gonads reaching first sexual maturity, females with more expanded abdomens; (k) 360DPH sexually mature male, with spatulated fertilized eggs in red circle"

Tab. 3

Comparison of the characteristics of fertilized eggs and first hatchlings of S. nematoptera and other cardinalfish"