Fig. 3.

(A and B) Tail-flapping frequency $f$ (Hz) (A) and tail-flapping amplitude (nondimensionalized by fish body length) (B), as a function of the swimming velocity $U$ (in body lengths per second). (C) Transverse Reynolds number, $R{e}_t=⟨f⟩⟨A⟩⟨L⟩/⟨\nu ⟩$, as a function of the cruising Reynolds number, $R{e}_U=⟨U⟩⟨L⟩/⟨\nu ⟩$. (D) Evolution of the synchronization parameter $s^{\ast }=S/(S+NS)$ that represents the cumulative probability of a synchronized state between nearest neighbors, as a function of the swimming velocity $U$ (see Table S3).