HI-stellar mass relation (upper) and the HI-stellar mass ratio as a function of stellar mass (lower) for a sub-sample of Fornax, satellites, and field galaxies in our work as labelled. Arecibo Observatory and Green Bank Telescope targeted observations by Geha et al. (2006) of optically selected dwarfs and ALFALFA detections (both for SDSS galaxies) from Durbala et al. (2020) are also included for reference. The offsets between the datapoints in our sub-samples, the Geha et al. (2006) work and ALFALFA is expected when galaxies are optically selected (see text for details). Arrows show HI upper limits where reported in the respective catalogues.