In the trunk and tail, the DLAVs continue to anatomose slightly further cranially. The longitudinal VTA and PAV extend across most of the trunk segments, but some are incomplete yet. By 7 dpf many VI have extend the full D-V length of the ventral vertical septum boundary, and some dorsal branches from LB have also begin to appear along the dorsal transverse septa, although circulation is weak through these and they are poorly visualized. Microscopic observations indicate that the dorsal branches have their arterial root at the dorsal tip of intersegmental arteries while the ventral intercostals have their root at the dorsal aorta. Both dorsal and ventral branches drain into the intersegmental veins at the level of the PCV.

The SBA is now an elaborate set of many looped, branched vessels on the ventral surface of the inflated swim bladder [6.5 dpf overview], [7.5 dpf overview]. With the complete loss of the yolk, the left cranial SIV degenerates except at its cranial most end, which drains into the hepatic sinusoid. The separate, additionally developed intestinal veins now play a major role for the ventral territory of cranial midgut as HPVs [intestinal vasculature]. All of the SIVs and supplementary intestinal veins drain into the liver via the ventral midgut wall, and show no sign as yet of the secondary hepatic portal vein that will presumably (as occurs in other vertebrates) later detour across the gut at the dorsal boundary between fore- and mid-gut.

In the branchial arch system, the ALB continue to grow, proliferate, and -elaborate. The further changes in these vessels have not been characterized as a part of this study. In the cranial vasculature, major vessels are relatively unchanged in their patterns of connections, but extensive remodeling and shifting of vessels, particularly smaller caliber vessels and capillaries, continues throughout this period. It should be noted that we have not observed up to this stage, and have still not confirmed the later appearance of, the direct connection between the BA and VTA that is seen in all other vertebrates (see discussion).