Polyphyllus is one of the few kind of Fissidens that grows underwater in the natural habitat. Its unique design makes it one of the most desirable Fissidens in aquaristic, next to G. Plannicaulis or Fissidens "Bucephalandra". Its sharp leaves looks magnificent.
On the market egsist another Polyphyllus, whose name was incorrectly specified. True Polyphyllus should looks just like I presented on photos. It has a diagonal and sharp leaves.