Zebrafish (Danio rerio) Platelet-Derived Growth Factor-BB (PDGF-BB) is a homodimeric growth factor composed of two PDGF-B chains that plays an important role in cell proliferation, migration, angiogenesis, and tissue development in teleost fish. PDGF-BB signals primarily through platelet-derived growth factor receptors (PDGFRs), particularly PDGFR-β–like receptors, activating intracellular signaling pathways such as PI3K/AKT, MAPK, and STAT, which regulate mesenchymal cell growth, vascular development, and extracellular matrix remodeling. In zebrafish, PDGF-BB is expressed by endothelial cells, fibroblast-like cells, and developing mesenchymal tissues, where it contributes to blood vessel formation, pericyte recruitment, and organ development during embryogenesis. PDGF signaling is also important for tissue regeneration, including heart, fin, and vascular repair, processes that are highly active in zebrafish. Because zebrafish embryos are transparent and genetically tractable, PDGF-BB signaling can be studied in vivo using fluorescent reporter lines and gene-editing approaches, making zebrafish a powerful model for investigating angiogenesis, vascular remodeling, and regenerative biology. Characterization of zebrafish PDGF-BB therefore provides important insights into conserved growth factor signaling pathways, tissue regeneration mechanisms, and vascular development relevant to vertebrate biology and human disease.