Gas metallicity of the clumps in the tail. The clumps are shown as different symbols denoting the different analysis times. Left panel: Gas metallicity as a function of the mass fraction of gas that at some point during the simulation has resided in the jellyfish galaxy’s ISM. During infall (2.50 and 2.75 Gyr), there is a correlation between these two quantities. This indicates that the metallicity of the jellyfish tail is influenced by mixing of high-metallicity ISM gas with low-metallicity gas from the CGM and ICM. We quantified this with a ‘mixing model’, $Z/{\mathrm{Z}}_{\odot }=\frac{2}{3}f(\mathrm{through}\mathrm{ISM})+\frac{1}{3}$, that assumes that the ISM metallicity does not evolve. After the closest passage in the cluster (3.25 Gyr), a clear majority of the gas in the tail clumps has resided in the ISM during the simulation, and we observed a higher metallicity than predicted by the non-evolving mixing model. Right panel: Plot of the metallicity as a function of distance downstream from the galaxy. We found a declining trend after the central passage. Before the central passage, we also observed a decreasing trend in the immediate tail within ≲80 kpc of the galaxy. This is a signature that mixing is more important further downstream than in vicinity of the galaxy.