The invention provides cells or populations of cells, including non-human animals or non-human mammals having these cells, where the cells or populations of cells are stably tagged, uniquely identified and genetically barcoded by one or more detectable, e.g., fluorescent, proteins and methods of making and using them. In alternative embodiments, the invention provides methods for tagging, uniquely identifying or genetically barcoding a cell, a population of cells, or a culture of cells by stably transferring, transfecting, transducing, infecting or implanting one or more nucleic acids encoding readable or detectable, e.g., fluorescent, moieties into the cells. In alternative embodiments, the nucleic acids are stably inserted into the cells such that the readable or detectable, e.g., fluorescent, genetic barcoding becomes a stable, heritable characteristic of the cell. In alternative embodiments, the invention provides fluorescent barcoded multiplexed cell-based assays using several different fluorescent proteins. The multiplexing power of methods of the invention can be increased by combining both the number of distinct fluorescent proteins and the fluorescence intensity in each channel.