The lake is triangular in shape, with its apex in the west, a bund, called the Dhussi Bund forming one side, a canal the second and a major road the third. The Harike barrage connects Amritsar city with Ferozepur, Faridkot and Bhatinda by a national highway. Of the present sanctuary area, 73 sq km constitutes a wetland enclosing shallow, marshy tracts that serve as perfect feeding and wading habitat for waterfowl. Tree covered earthen mounds have been constructed in the marsh area, to increase nesting sites for the birds.

Harike is a vital staging post and the winter home of a enormous concentration of migratory waterfowl that rivals only Keoladeo National Park near Bharatpur. Over 20,000 ducks have been recorded here during the peak migratory season. A number of globally threatened species have also been recorded in Harike. During the winter, about 200 species of birds visit the lake, including migratory as well as resident. From 1980-1985, the Bombay Natural History Society (BNHS) carried out research and a bird ringing program there. Harike was also the subject of a 1994 publication by WWF-India as part of their series on Ramsar Sites of India.

In addition to the common birds, other important species that can be seen here are Cotton Pygmy Goose, Tufted Duck, Yellow-crowned Woodpecker, Yellow-eyed Pigeon, Watercock, Pallas's Gull, Brown-headed Gull, Black-headed Gull, Yellow-legged Gull, Indian Skimmer, White-winged Tern, White-rumped Vulture, Hen Harrier, Eurasian Sparrowhawk, Eurasian Hobby, Horned Grebe, Black-necked Grebe, Great Crested Grebe, White-browed Fantail, Brown Shrike, Common Woodshrike, White-tailed Stonechat, White-crowned Penduline Tit, Rufous-vented Prinia, Striated Grassbird, Cetti's Bush Warbler and the Sulphur-bellied Warbler.

Some 7 species of turtle and 26 species of fish have been recorded in Harike. The mammals found at Harike include the Smooth Indian Otter, Jungle Cat, Jackal, Indian Wild Boar and the Common Mongoose. The rare and endangered Testudine Turtle and Smooth Indian Otter are listed in the IUCN Redlist of Threatened Animals. Harike attracts large populations of avifauna, in particular the diving ducks. It is a vital source of water for the people of Punjab. The main species of fish fauna present is Hilsa. The livelihood of nearby villagers depends to some extent upon the lake's fish resources.

Amongst phytoplankton, the Bacillariophyceae is represented by about 10 species. An extensive growth of Typha elephantina and Phragmites karka is observed along the margins of the lake, in surrounding low lying areas, as well as in the upstream Mand area. Of free floating plants, Azolla, the nitrogen fixing fern, occurs in patches of open water. The tall grasses Saccharum spontaneum and S. bengalenses are common along the higher ground in the wetland area and on slopes and margins of surrounding bunds and dykes. Tamarix diocia is the sole woody plant adapted to an aquatic habitat found in the area; rest of the trees are upland species.

The major threats to this important wetland include; large scale utilization of both surface and ground waters for irrigation, expansion of intensive agriculture resulting in encroachments on the wetland, drainage of agricultural chemicals into the waters, discharge of untreated waste from catchment towns into the rivers which feed the wetland, and deforestation of the lower Shivalik hills, causing soil erosion and silting. The Indian Army in the year 2000, along with other agencies launched and completed a major project to clear water hyacinth, which was almost choking the lake.