Coral Moss (Riccardia chamedryfolia or Mini Pellia)

Riccardia chamedryfolia, the jagged germanderwort, is a species of liverwort, a terrestrial plant which has been adapted by aquarist as an ornamental plant for the freshwater planted aquarium hobby. It is also known as Mini or Coral Pellia due to its growth similarity to coral when submerged underwater). Wikipedia