Nymphaea tetragona is an aquatic perennial,[3] species of flowering plant commonly called pygmy waterlily[4] and small white water lily,[5] belonging to the family Nymphaeaceae.

[11] Its distribution encompasses Midwestern Nepal, China, India, Japan, Kashmir, Kazakhstan, Korea, Russia, Vietnam, North America, and Europe.

[12] Nymphaea tetragona inhabits ponds, lakes, and quiet streams;[5] and it is native to the region spanning from North Europe to Korea and Himalaya, and Subarctic America to Northwest USA.

[13][14] The mature fruits on the plant decay to reveal the seed and remain buoyant for approximately a day which is important for dispersal[14] because the habitat of N. tetragona tends to encompass calm waters like ponds, swamps, lakes, or streams.

[13] The establishment of the seed in the appropriate ecological conditions for N. tetragona to thrive and reproduce is considered to be more important than dispersal ability which appears to generally be sufficient.

[20] Furthermore, it was used to treat ailments like diarrhea with dysentery, enteritis, fever, painful urine discharge, and urinary passage infections in folk medicine.

[20] N. tetragona is the first species in the family Nymphaeaceae to have Geraniin isolated and it showed evidence of inhibiting disease causing bacteria in fish.

[20] Furthermore, a specific application for a 50% methanol extract of N. tetragona has been proposed as a part of an antimicrobial treatment in combination with antibiotics for fighting against the bacterial resistance of a Salmonella infection in humans and animals alike.