aortic arch aortic arch 5 AA5 TAO:0005009 The fifth and sixth arches, which come on-line at approximately 2.5 dpf, have a common trunk from the ventral aorta and drain to the midline dorsal aorta via an independent route. The fifth and sixth aortic arches supply the trunk and tail with oxigenated blood. Isogai et al. 2001. teleost_anatomy