Mekong Giant Catfish, also known as Thailand Giant Catfish, is the largest fresh water catfish in the world. Once abundant in the grand Mekong river, the giant catfish population has reduced drastically in last few decades. Now this species is considered as Critically Endangered.
Mekong giant catfish is endemic to the middle and lower basin region of Mekong. Originally the fish had a natural range that reached from the lower Mekong in Vietnam all the way to the northern reaches of the river in the Yunnan province of China, spanning almost the entire 4,800 km length of the river. Due to threats, this species no longer inhabits the majority of its original habitat; it is now believed to only exist are small, isolated populations in the middle Mekong region. It is a migratory species and can only thrive in fresh water. Each year from October to December, this fish moves out of the Tonle Sap Lake in Cambodia into the mainstream of the Mekong River. From there, it is believed to migrate upstream into northeastern Cambodia and possibly Laos, or Thailand to spawn. The Mekong giant catfish can also be seen occasionally in the Chao Phaya River. When feeding fish at the Bangkok temples along the river, the fish will be seen at times.
The quality of the water in the Mekong basin has been reduced due to development and upstream damming by China. Fishing has been banned in Thailand, Laos, and Cambodia but the ban has helped little.But in Thailand it is allowed fishing for private stocks of Mekong giant catfish. This helps save the species as lakes purchase the small fry from the government breeding program, generating extra income that allows the breeding program to function.
Presently research projects are ongoing, but relatively little is known about the Mekong Giant Catfish. The infant catfish feeds on zoo plankton in the river and is known to be cannibalistic too. After reaching one year of age, the fish becomes herbivorous, feeding on filamentous algae, probably ingesting larvae and periphyton. The fish likely obtains its food from algae growing on submerged rocky surfaces, as it does not have any sort of dentition. Very little is known about its reproductive behavior. Fish congregate during the beginning of the rainy season and migrate upstream to spawn.
The Mekong Giant Catfish is the largest fresh water fish in the world. Adults can reach over 9.8 feet in length and can weigh over 300 kg(650 lb). The species also has one of the fastest growth rates of any fish in the world and can reach up to 200kg by its sixth year. The skin of the giant catfish is gray to white in color with no stripes, and this fish is distinguished from other large catfish in the Mekong by its lack of teeth and the almost complete absence of barbels.
The largest ever recorded Giant catifish caught in Mekong is nearly nine feet long (2.7 meters) and 293 kg (646 lb). This was caught in 2005 by a team of fisherman in Northern Thailand.