Wallemia ichthyophaga is one of the three species of fungi in the genus Wallemia, which in turn is the only genus of the class Wallemiomycetes. The phylogenetic origin of the lineage was placed to various parts of Basidiomycota, but according to the analysis of larger datasets it is a (495-million-years-old) sister group of Agaricomycotina. Although initially believed to be asexual, population genomics found evidence of recombination between strains and a mating type locus was identified in all sequenced genomes of the species.
Only a limited number of strains of W. ichthyophaga have been isolated so far (from hypersaline water of solar salterns, bitterns (magnesium-rich residual solutions in salt production from sea water) and salted meat).