Hygrophila polysperma

Hygrophila polysperma is native to the shallow, slow-moving waters and flooded fields of India and Southeast Asia, where it grows prolifically in warm, nutrient-rich environments. It is considered one of the easiest aquarium plants in existence, capable of surviving conditions that would kill most other aquatic plants — fluctuating pH, hard tap water, low light, and even minimal water movement. In the aquarium hobby it has been a staple for over a century, introduced early in the modern era of fishkeeping as a reliable green plant for community tanks. Its small, paired leaves range from bright green to reddish-pink under high light, and the variety 'Rosanervig' features striking pink venation. Despite its ease, Hygrophila polysperma grows at an impressive rate and can quickly dominate a tank if left untrimmed, making regular maintenance important. It is extremely effective as a biological filter supplement, consuming nitrates and phosphates rapidly. The plant is classified as invasive in parts of the southern United States where it has escaped into waterways, so proper disposal of trimmings is essential.