Table 1. Drag-thrust decomposition of free swimming black ghost knifefish fin, eel, larval zebrafish. Also shown is the decomposition of a hypothetical fin with mackerel kinematics. The amplitude shown for the knifefish is at distance of 0.75 cm from base of the fin. The range for x in A(x) is [0, 1]. Undecomposed forces equal to zero indicate free swimming cases.

	Knifefish	Eel	Zebrafish (larval)	Mackerel
Amplitude (cm)
Amplitude function A(x)	Experimental13	0.15e(x−1)19	Experimental	0.02 − 0.08x + 0.16x2 18,20
Thrust force T (mN)	1.43	6.8 × 10−4	4.3 × 10−3	11.6 × 10−3
Drag force D (mN)	1.48	8.2 × 10−4	4.1 × 10−3	46.8 × 10−3
Undecomposed force F (mN)	0	0	0	21.4 × 10−3
Net force D − T (mN)	0.05	1.4 × 10−4	−0.2 × 10−3	35.2 × 10−3