Improvement grant funding of $700,000.00 is requested for the expansion and equipping of an existing zebrafish housing and breeding facility in the School of Medicine at the University of Washington. This project is responsive to to a critical need for additional space in which to house zebrafish. In the past few years the need for zebrafish housing in the School of Medcine has risen from literally a few tanks to over 1100. This need has been driven by the increased recognition of the value of this animal model as well as by recruitment of scientists who utilize zebrafish as a major aspect of their research efforts. This shared facility (Zebrafish Combined Resource Facility) will support the research of 6 NIH-supported investigators (5 current and 1 newly recruited) from 3 departments within the School of Medicine. The availability of this expanded space will also relieve pressure on other (principally rodent) animal housing space for which zebrafish housing must compete. The proposed renovation will consist of an approximately 400 sq. ft. contiguous expansion of an existing zebrafish facility and will include all necessary tanks, racks and water handling equipment to make it fully functional. By adding on to an existing facility there is a gain in efficiency in regard to animal care and transport as well as development of redundant essential water handling and filtering equipment, allowing duplicate housing of valuable strains. This space will also incorporate microinjection equipment which is currently housed in a separate facility. With the expanded space transport of eggs for injection outside of the zebrafish facility will no longer be necessary. In addition we are requesting funding to purchase additional tanks and support equipment to increase housing in an existing zebrafish room. All together this will increase the total number of tanks from 1105 to 2325 - an increase of approximately 110%. Oversight of these facilities will be the responsibility of the Department of Comparative Medicine which has programmatic responsibility for all animal facilities on the University of Washington campus.