The zebrafish genetics toolkit has been missing a particularly handy piece of kit: a promoter to drive ubiquitous transgene expression throughout development, equivalent to the Rosa26 locus used in mouse genetics. But no longer, for in one of Development's inaugural Technical papers (p. 169), Leonard Zon and co-workers report that the zebrafish ubiquitin (ubi) promoter can drive constitutive transgene expression throughout development. The authors initially identified ubi in BLAST searches using human ubiquitin. They then tested a 3.5 kb 5' region upstream of its translational start site for transcriptional regulatory sequences and found that it drives strong and ubiquitous EGFP expression within 4 hours of injection into a single-cell embryo. Moreover, in stable ubi-EGFP transgenic lines, EGFP is strongly expressed in all external and internal organs they analysed, in all blood cell types, and from embryo to adulthood. The authors also created inducible ubi-driven CreERt2 transgenes and loxP lineage-tracer transgenes that give strong reporter activity upon Cre exposure, which further enhances and expands the zebrafish transgenesis toolkit.