The Big Tengra Fish, also known as Mastacembelus armatus, is a species of freshwater fish native to South and Southeast Asia. It belongs to the family Mastacembelidae and is known for its elongated body and spiny fins. Often found in slow-moving rivers and lakes, it has a distinctive appearance with a long, snake-like body and sharp spines along its dorsal fin. The Big Tengra Fish is popular in aquarium trade and is known for its predatory behavior. It can grow to lengths of up to 3 feet.