A Closer Look at the BG-5 Golden Dragon Fish, China’s Robot Arowana That Swims Without a Script

Crowds in Hall 3 at Beijing’s Shougang Park last week kept stopping at a small tank. A slender golden fish with layered scales was rising, sinking, and turning with a soft flick of its tail. Only after it changed course on its own did most people accept they were watching a machine, not an arowana that had wandered into a trade-fair display.

Boyagongdao Marine Technology Group debuted the BG-5 Golden Dragon Fish at the 2026 China International Fair for Trade in Services, and it was a huge hit. The robot is essentially a replica of the arowana’s long body and glossy gold coloring, down to the details. According to the catalogue’s specifications, it is 640 millimeters long, 204 millimeters wide, and 90 millimeters high, weighing around 3 kilograms. It is supposed to be capable of operating at depths of up to 5 meters and reaching speeds of up to 0.6 meters per second.

According to those working on the exhibit, the fish was not programmed with a predetermined course; instead, the robot’s onboard sensors detect its surroundings and plans a new path as it goes. That’s kind of the purpose; canals, lakes, and tunnels change all the time, and a human operator just cannot keep up with every twist and turn.

The propulsion system is quite interesting, as it is a flexible tail with three joints divided into seven segments that work together to send a wave down the fish’s body, just like a real fish. There are no spinning propellers, so it’s much quieter and less noticeable than your usual underwater drone. All of the electronics are safely stored in the main cabin, which includes all of the high-precision sensors and a fancy global vision control system you’d expect for a task like this, as well as a modular layout to make servicing easy.

They have a version called the BG-5V that not only conducts path planning, task allocation, and formation control, but it can also coordinate with multiple units, so you could have a number of these robots working together to cover different parts of the ocean at once. This seems very fascinating, and it demonstrates how the same technology can be used for both a tank demo and a more complex work.

The device’s small size is also a significant advantage, since it can fit into shallow water and tight channels that larger drones cannot. Furthermore, it is meant to be quiet, allowing you to join a school of genuine fish and observe marine life, or to slide through water tunnels and hydropower sites without disturbing anything. The battery life and camera resolution were kept under wraps, although they did indicate it’s good for 5 meters, so it’s not a deep-ocean submarine. Even still, the combination of a looker that resembles an expensive aquarium fish, a tail that moves like one, and some extremely intelligent sensors is not difficult to understand, as this is a company with substantial underwater knowledge and the possibility for even more…