A plant sold as Monosolenium tenerum and commonly known as Pellia or Pelia was made popular as a freshwater aquarium plant by Tropica is now sold as Monosolenium tenerum . A similar plant, known in the hobby as " Süsswassertang " is often sold as Round Pellia or Round Pelia , but neither of these names is correct. Süsswassertang is now known to be the gametophyte of a species of fern , of the genus Lomariopsis (wikipedia)