<p> Burial is an important life history strategy employed by benthic fishes that has not been fully explored in its diversity by the biomechanical literature. This thesis explores the mechanism by which the Pacific sandfish buries as well as the physical limitations of the behavior. We first investigate the role of the ventilatory pump in the burial behavior of sandfish by using high-speed videography, dye, and digital particle image velocimetry (DPIV). We determined that sandfish employ a modification of the ventilatory pump, which is used repeatedly to fluidize the substrate ventral to the head. This modification of the ventilatory pump should reduce the energetic costs associated with burial as it decreases the cost of transport typically associated with &lsquo;shoveling&rsquo; substrate. Second, we investigate the physical limitations that are caused by the reliance on the ventilatory pump to fluidize substrate. We used sand beds of varying grain sizes, and therefore varied the minimum velocities of fluidization, to determine how sandfish respond variation in substrata. We determined that sandfish can bury in grains smaller than 1.00mm in diameter but were unable to bury in any substrate larger than 1.00mm. We also determined that there was an increase in the time it took sandfish to bury in those substrates smaller than 1.00mm as grain size increased. There was no change in the frequency of the behavior, however, suggesting that sandfish have very little ability to bury in larger substrates. We also determined that it is probably not the absolute velocity produced by the opercular jet that determines burial success, but the ability burying behavior to maintain the sand&rsquo;s momentum during the expansive phase that occurs between bouts of opercular jetting.</p>