The most visible difference between crocodile and Gharials is that of their snouts. While the snout of crocodile is short and wide that of gharial is slender and much longer. Crocodiles have a grinning look with their upper and lower teeth interlaced outside even when the mouth is closed, although the number of teeth in gharial is much more than that of crocodiles, they remain closed in.
This snout structures found in both animals is suited for their independent feeding habits. As crocodiles feed bigger preys compared to gharials which feed on fish and smaller animals.
The population of gharial is lower than that of crocodiles. As a matter of fact, gharial was considered to be going extinct owing to a population decrease of about 98% in the last 75years.