The basic imaging process for MERFISH involves several fluid handling steps, e.g. introduction of hybridization buffers and wash and imaging buffers, in conjunction with the collection of smFISH images and the photobleaching of the sample. While it would be possible to perform these fluid exchange and imaging steps manually, we strongly recommend the use of an integrated and automated fluid exchange and imaging approach. Here we provide protocols for how to construct a fluid handling system that should be compatible with a variety of microscopes. We also discuss the basic protocols for hybridizing readout probes to samples on the microscope, imaging the sample, and bleaching residual signal.