Redshifted wavelengths of strong emission lines in the rest-frame optical (crimson: [S II]λ6724, red: [N II]λ6584, yellow: Hα, green: [O I]λ6300, cyan: [O III]λ5007, blue: Hβ, and purple: [O II]λ3727) and their resulting detectability using Euclid’s blue grism (BGS, blue shaded area) and red grism (RGS, red shaded area). The redshift bins used for the following analysis (vertical dashed lines) were chosen according to the overlap of observed wavelengths with the BGS and RGS sensitivity ranges, 0.93–1.37 μm and 1.21–1.89 μm, respectively.