To determine the effect of fish age on the swimming speed of larvae from hatching through the onset of settlement, we evaluated the swimming speed (Ucrit) of A. percula larvae at 0, 4, and 8 dph (day post hatch), and of E. lori and E. colini at 0, 10, 20, and 30 dph . At the start of each trial, an individual larva was acclimated to the flume for 2 min with water flowing at a velocity of < 1 cm s-1. If the larva displayed normal orientation and swimming behavior during acclimation, then the velocity was increased 2 cm s-1 every 2 minutes until the larva could no longer maintain position and was either expelled from the flume or collected on the back mesh. Following trials, recollected larvae or siblings from the same clutch were photographed using a dissection microscope, and photos were measured for standard length using ImageJ (NIH, USA; Table 2). A larva’s maximum swimming speed (Ucrit) was then calculated following the equation from Brett (1964).