The Ganges River is home to many different species of fish, amphibians, reptiles and mammals. The Ganges-Yamuna area was once densely forested. Historical writings indicate that in the 16th and 17th centuries wild elephants, buffalo, bison, rhinoceroses, lions, and tigers were hunted there. Most of the original natural vegetation has disappeared from the Ganges basin, and the land is now intensely cultivated to meet the needs of an ever-growing population. Large wild animals are few, except for deer, boars, and wildcats and some wolves, jackals, and foxes. Only in the Sundarbans area of the delta are some Bengal tigers, crocodiles, and marsh deer still found.

There are an estimated 140 fish species and 90 amphibian species in the Ganges River. Fish abound in all the rivers, especially in the delta area, where they form an important part of the inhabitants’ diet. In the Bengal area common fish include featherbacks (Notopteridae family), barbs (Cyprinidae), walking catfish, gouramis (Anabantidae), and milkfish (Chanidae) but the Fish growth has slowed significantly. The Ganges river dolphin—or susu (Platanista gangetica), a nearly sightless cetacean with highly developed sonar capabilities—can be found throughout the Ganges-Brahmaputra basin, but it is considered endangered because of encroaching human activity. Many varieties of birds are found, such as mynah birds, parrots, crows, kites, partridges, and fowls. In winter, ducks and snipes migrate south across the high Himalayas, settling in large numbers in water-covered areas. Today, the severe pollution levels are a threat to all the animals, living beings in and around the Ganges River.

The basin size of the Ganges River is over 500,000 square miles.The Ganges basin is one of the most densely populated regions on earth. The untreated sewage dumped into the river, industrial waste, agricultural runoff, remnants of partially burned or unburned bodies from funeral pyres, and animal carcasses all contribute to polluting the Ganges. High levels of disease-causing bacteria and toxic substances have also been found in the Ganges.

Hundreds of millions of litres of filthy water reach the Ganges every day, according to the latest data. It's one of India's most polluted rivers. It nevertheless has a significant capacity for self-purification due to its sheer size and amount of water.

Though it is known that the villagers worship this river as a deity. But nowadays, One of India’s key issues is Ganga pollution. The main source of pollution in the Ganga is industrial effluents. Several manufacturers, such as rubber, plastic, and leather, have sprung along the river’s bank and discharge their waste into the water. As a result, life under the ocean suffers. According to a recent survey, the river receives roughly 1 billion gallons of unprocessed, raw sewage. Another form of Ganga pollution is the dumping of human and animal carcasses into the river. Many human remains have been found strewn on the river’s ghats and submerged in the water. The government has taken a number of steps to combat Ganga pollution. To address this dilemma, we need stretch our hands.

1. Marine life

Mercury study of several specimens collected along the basin revealed that some fish muscles tended to acquire high mercury levels. Organic mercury made up about 50–84 percent of it. A considerable positive link was discovered between mercury levels in muscle and eating habits as well as fish length.

Water pollution in the Ganges River is caused by sewage discharge, industrial waste and plastic objects. The Ganges river dolphin is one of just a few freshwater dolphin species found worldwide. Their number is estimated to be less than 2000, making them an endangered species. The main reason for the dolphins’ population decline is hydroelectric and irrigation dams along the Ganges, which prohibit them from travelling up and down river. The Ganges softshell turtle (Nilssonia gangetica) can be found in Pakistan, northern India, Bangladesh, and southern Nepal along the Ganges, Indus, and Mahanadi river systems. This turtle prefers mud or sand beds in deep rivers, streams, huge canals, lakes, and ponds. Freshwater turtle species are endangered, according to the International Union for Conservation of Nature. Turtles are vulnerable to heavy metal contamination, which is a major source of pollution in the Ganges, because of their long lifetime and high trophic level in the aquatic food web.

2. Wildlife

Some of the dams being built throughout the Ganges River basin would submerge large sections of nearby forest. The Kotli-Bhel dam in Devprayag, for example, will sink 1200 hectares of forest, obliterating the forest and, with it, the fauna.

3. Humans

In 2006 and 2007, a study of the Ganges water revealed substantial links between water-borne/enteric disease and river use for bathing, laundering, washing, eating, cleaning utensils, and brushing teeth. There are an estimated 400 million people living near the Ganges River. The water in the Ganges has been linked to dysentery, cholera, hepatitis, and acute diarrhoea, which continues to be one of India’s major causes of child mortality. Not only animals, Humans are also threated by the large levels of pollutants in the Ganges River.