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Typical endoscopic observations inside the oropharyngeal cavity of carp during feeding on Tetramin particles off a gravel substrate (125 frames s^-1, duration of sequence 968 ms).  The anterior of the fish is to the bottom of the image.  Rows of gill rakers on ceratobranchials I-IV are visible on the right, and the palatal organ is visible on the left.  In this sequence, a rock is pressed down and pinned by the palatal organ across ceratobranchial IV.  Tetramin particles (0.1—1.0 mm diameter) and brine shrimp cysts (210—300 mm diameter) travel posteriorly past the rock and do not come into contact with any pharyngeal surface while in the field of view.

Endoscopic video showing a typical protrusion of the palatal organ of carp during feeding on Tetramin particles (0.1—1.0 mm diameter) off of a sand substrate (500 frames s^-1; duration of sequence 80 ms).  The anterior of the fish is to the right.  The palatal organ is visible above ceratobranchials I and II.  After a protrusion of tissue from the palatal organ is shown contacting ceratobranchial II, a sand grain enters the field of view on the left side of the protrusion during a flow reversal.  The sand grain then passes lateral to the protrusion.  The protrusion begins to move dorsally and lifts from ceratobranchial II while the water is still moving anteriorly during the flow reversal.

Typical endoscopic observations of feeding on bass pellets (0.6 cm diameter) by carp off a gravel substrate (30 frames s^-1; duration of sequence 267 ms).  The anterior of the fish is to the right.  The palatal organ is visible above rows of gill rakers on ceratobranchials I-III.  A pellet is pinned across ceratobranchial III by an overall height reduction of the pharyngeal slit.  Three rocks then enter the field of view and are eventually spat anteriorly out of the field of view while the pellet is retained by a palatal protrusion.