Inspired by the Black Ghost Knifefish: Bionic Design of Undulatory Fin with 2-DOF Rays and Its Propulsion Performance

Table 1

Morphological data of each part of ventral fin.

	Amount (rays)	Length (mm)	Average-length of fin rays (mm)	Aspect ratio
Fore fin	26	7 (1/8)	2.3	3.04
Mid fin	99	42 (3/4)	5.5	7.64
Rear fin	28	7 (1/8)	2.4	2.92