The Cre-loxP recombination system is widely used as a genetic tool to achieve conditional gene expression and for lineage tracing. Though extensively used in mice, this technology has only recently been applied to zebrafish. Here we describe Cre-loxP methodology for conditional expression of transgenes in zebrafish and their use in lineage tracing Müller glia as they undergo cellular reprogramming and proliferation to repair damaged retinal circuitry following mechanical injury. This methodology can be used for conditional gene expression and lineage tracing at any stage of development and in any cell type.