Understanding how different organs age at the molecular level could revolutionize personalized longevity interventions, yet comprehensive cross-tissue aging maps remain scarce in vertebrate research. The discovery of tissue-specific aging signatures offers new precision beyond chronological age alone. Scientists constructed the most comprehensive vertebrate aging atlas to date using African turquoise killifish, analyzing gene expression changes across 13 tissues at six life stages in both sexes. This short-lived vertebrate model revealed that aging unfolds differently across organs, with some tissues showing pronounced sex-specific patterns while others follow more universal trajectories. The research identified evolutionarily conserved aging pathways shared with mice and humans, suggesting fundamental mechanisms that transcend species boundaries. Notably, female killifish displayed a distinctive shift toward myeloid cell dominance in blood-forming tissues with age, a finding that may illuminate sex differences in immune aging across vertebrates. The team developed tissue-specific 'transcriptomic clocks' that predict chronological age with remarkable accuracy, representing a significant advance over single-tissue approaches. These molecular timepieces successfully evaluated the effectiveness of various lifespan interventions, demonstrating their utility as precise aging biomarkers. The work establishes killifish as an exceptional model for aging research due to their short 4-6 month lifespan and genetic similarity to humans. This comprehensive dataset provides researchers worldwide with unprecedented granular insight into how aging manifests differently across organ systems, potentially accelerating the development of targeted anti-aging therapies that address specific tissue vulnerabilities rather than applying broad interventions.