NHGRI intends to award a firm-fixed-price purchase order solely to Aquaneering LLC to retrofit and expand its existing aquatic housing system by converting eight underutilized genotyping rack positions into standard zebrafish housing, adding capacity for 828 tanks and more than 25,000 zebrafish, with tanks excluded. The retrofit must be fully compatible with NHGRI’s existing Aquaneering central-filtration system, tanks, and plumbing interfaces, and includes specified 60-inch and 50-inch racks, containment trays, water manifolds, gutters, downspouts, opaque flexible tubing, and a custom supply-and-return plumbing kit. The work also requires relocating existing racks and integrating new and existing components within the approved room layout and plumbing isolation points. The Government justifies a sole-source award under FAR 6.302-1 because only Aquaneering can maintain compatibility with the installed system and avoid integration, cost, and operational risks. The Government anticipates award about five calendar days after the notice closes, and interested parties may submit capability statements to demonstrate they can meet all technical and operational requirements.