How Garibaldi Got Its Red Coat: The Genome of Hypsypops rubicundus , a Conspicuous Fish of the Northeastern Pacific Kelp Forests

Coloration in fishes plays central roles in communication, defense, and sexual selection, and is mediated by specialized pigment cells (chromatophores). In many species, red and orange hues derive from dietary carotenoids that are metabolically modified and intracellularly transported. The Garibaldi, Hypsypops rubicundus , a long‐lived and iconic damselfish endemic to the eastern Pacific, displays a striking carotenoid‐based orange‐red coloration. To provide genomic resources for studying coloration genes in this species, we generated and assembled a high‐quality genome using Oxford Nanopore long reads, yielding a 781.7 Mb assembly with 96% BUSCO completeness. As a proof of concept, we investigated the carotenoid‐associated transport gene kif5b, which encodes a kinesin‐1 motor protein involved in intracellular pigment mobilization. The kif5b gene in H. rubicundus comprises 25 exons and shows conserved organization relative to other damselfishes, but exhibits a unique amino acid substitution within a conserved nucleotide‐binding motif (N3). Specifically, position 238 contains a leucine in H. rubicundus , whereas other damselfishes possess a glutamic acid or serine at this site. This substitution replaces a polar residue with a hydrophobic one, potentially affecting protein conformation or function. Phylogenetic analyses based on mitochondrial genomes and kif5b exons were largely congruent with published relationships. Our results establish the H. rubicundus genome as a valuable resource and identify a candidate molecular change that may contribute to its distinctive carotenoid‐based coloration.