The name Flavihumibacter fluminis Park et al. 2022, which was effectively published but invalidated, is an illegitimate homonymic epithet of Flavihumibacter fluminis Guo et al. 2023. The low 16S rRNA gene sequence similarity and genomic relatedness between the type strains IMCC34837T and RY-1T of the two homonymic species indicated that they are different species. To avoid further confusion, we propose a new name Flavihumibacter fluvii sp. nov. to replace the effectively published but invalidated homonymic epithet Flavihumibacter fluminis Park et al. 2022.