Scientists working in Thailand’s Mae Klong River made a big find last week: an enormous stingray that they think is a contender for the largest freshwater fish ever documented by researchers.

The ray was caught and released in about 65 feet (20 meters) of water in the Amphawa District, about an hour outside Bangkok.

Nantarika Chansue, a veterinarian and professor at Chulalongkorn University in Bangkok, helped catch and measure what she calls the “big one.” The ray (Himantura polylepis or H. chaophraya) was 7.9 feet (2.4 meters) across and 14 feet (4.3 meters) long and weighed an estimated 700 to 800 pounds (318 to 363 kilograms), she said via e-mail.

The team was unable to get an exact weight because “it's