Nymphaea nouchali

Nymphaea nouchali, (or red and blue water-lily, blue star water-lily, or star lotus) is an aquatic flowering plant in the Nymphaeaceae (water-lily family). It is native to southern and eastern Asia.
"N. nouchali" grows from rhizomes or tubers rooted under the water. Leaves are oval to round, 13–15 cm (5–6 in), with an open sinus at the leaf base where it attaches to the petiole (leaf stem). Leaves may spread 1.4–1.5 m (4–5 feet) from where the rhizome is rooted. Flowers, which have little fragrance, are star-shaped with 4 sepals and 10–16 petals, and are 5–13 cm (2–5 in) in diameter. Although leaves float on the water surface, flowers are generally held 30 cm (12 in) above water. They are usually pale blue (but can be pink or white) with pale yellow stamens and anthers. 
"N. nouchali" has been cultivated in southeast Asia for centuries, especially around temples. It is also cultivated in Sri Lanka and gathered from dried ponds in the Republic of India for the rhizomes, which are used as food and animal fodder as a source of starch. In Ayurvedic medicine, it is used to treat indigestion.
Cultivars include N. stellata var. cyanea, which has medium-sized pale to deep blue flowers, and N. stellata var. versicolor, which is commonly exported in the form of tubers from Sri Lanka to Europe and the U.S. for use in the aquariums; the tubers grow quickly after exposure to warm water, making an “instant” aquarium plant.
Symbolism.
"N. stellata" was the state flower of Hyderabad Deccan. A pale blue-flowered "N. stellatai" is the National flower of Sri Lanka, where it is known as "nil mānel" or "nil mahanel" (Singhalese:නිල් මානෙල්).