Phenganax stokvisi is a zoantharian (family Hydrozoanthidae) found in tropical marine environments, growing epizoically on hydroid colonies with small, gracile polyps adapted to this unusual lifestyle. The systematic position of Phenganax within Zoantharia has been clarified through molecular phylogenetics, revealing its relationship to other epizoic zoantharian families. Its genomic data contribute to understanding the evolution of cnidarian-cnidarian epizoic associations in tropical marine environments.