Tide Fluor 5 is a fluorescent dye used for labeling oligonucleotides. Tide Fluor 5 has an absorbance maximum of 649 nm and an emission maximum of 664 nm, with spectral properties very similar to those of Cy5. Tide Fluor 5 has very high photostability, and its fluorescence is extremely high and insensitive to pH changes from 3-11. Tide Fluor 5 can be substituted for Cy5 in any FRET-based oligonucleotide assay, for example, TaqMan or Molecular Beacons, or as the reporter dye for fluorescent-based hybridization probes.