Boundary formation and maintenance are critical aspects of multicellular development. These processes have been well studied in the embryo; however, boundaries must be maintained beyond embryonic stages into adulthood. The pigment pattern of adult zebrafish offers a tractable system in which to study post-embryonic boundaries. It consists of four to five dark stripes of black melanophores separated by lighter interstripes of yellow xanthophores and iridescent iridophores. Positive and negative interactions between pigment cell types are required to initiate and reiterate this pattern, but homeostatic roles of these interactions are not well understood. While iridophores help position and terminate melanophore stripes, melanophores prevent iridophore expansion into the stripe region. Using a temperature-sensitive allele, we experimentally manipulated melanophore numbers during boundary maintenance to query effects on iridophore patterning. We find that iridophores accumulate ectopically in stripe regions when melanophores die, and disperse when melanophores differentiate. These observations suggest that melanophores prevent iridophores from trespassing into stripe regions and signal their presence via some molecular cue. We have identified candidate genes for such signaling by RNA-Seq, and we are using conditional CRISPR/Cas9 mutagenesis to test roles for these candidates during stripe maintenance. These data will further our understanding of the molecular bases for post-embryonic boundary maintenance which can then be used to explore how defects in these mechanisms lead to boundary failure in the context of human disease.