Rotala rotundifolia (variants include Rotala Colorata, H'ra, Ceylon, etc.) is a fast-growing stem plant that has long been a staple of the planted aquarium world. It was first introduced around 1960 under the misnomer Rotala indica, a confusion that continues to this day. A description of the true Rotala indica can be found here - along with an explanation of how the names got mixed up.
It is tolerant of a wide range of water parameters and is an easy plant to grow; it will even do well in aquariums without carbon dioxide injection after a period of acclimatisation. However, with sufficient light and CO2 it will grow with better density and colouration.
Family Name: Lythraceae
Origin: Southeast Asia
Height: 4-8”
pH: 6.5-7.5
Care: Easy
Light: High
Co2: 20-30ppm
Propagation: Cuttings
Growth Rate: Fast