Neuropeptides play crucial roles in regulating various physiological processes in vertebrates. In this study, we identified a novel neuropeptide-encoding gene, nwk, in the genomes of some vertebrate species. The nwk cDNA was subsequently cloned from the brain of zebrafish. The Nwk precursor comprises 88 amino acids, with a putative mature peptide (Nwk-22) of 22 amino acids. Sequence analysis revealed that Nwk-22 is relatively conserved across vertebrate species. Nwk is predominantly expressed in the brain, with positive mRNA cells identified in the TPp and preoptic area. Intraperitoneal injection of Nwk-22 suppressed food intake and downregulated the mRNA expression of the orexigenic factor agouti-related peptide (agrp) in zebrafish. Additionally, a CRISPR/Cas9 approach was used to generate nwk mutant zebrafish. The nwk