Researchers can easily visualize blood vessels in zebra fish by their endogenous alkaline phosphatase activity, by vessel-specific antibody staining, and, in transgenic zebra fish, with a vessel-specific promoter linked with a reporter, such as green fluorescent protein. After the lumen is formed, blood vessels can also be visualized by injecting fluorescent microbeads into the circulatory system as a functional assay to assess the integrity of the vascular
system