Significance A heart attack occurs when blood flow to part of the heart is blocked, and oxygen and nutrients are unable to reach that tissue, irreversibly damaging cardiac muscle cells. Dead muscle cells are replaced by a noncontractile scar that affects cardiac function. Unlike humans, zebrafish can regenerate their heart after injury, replacing the scarred tissue with new cardiomyocytes. Understanding the mechanisms zebrafish deploy to regenerate their heart may help us design more efficient therapies for human heart disease. In this study, we show that to regenerate their heart, zebrafish quickly revascularize the damaged area, and that this ability to revascularize is temporally restricted.