The Grass Sea Dragon, also known as the Common Sea Dragon, is a peculiar marine creature that lives in the waters off southern Australia and Tasmania. The body is made up of bony plates, covered in algae-like appendages that help them camouflage in the algae clump and hide from predators. Inhabiting mainly shallow marine reefs and algae-infested waters, it feeds on small crustaceans and plankton, has no teeth, and relies on elongated tubular sniffs for its prey. Poor swimming ability, limited range of activities, up to 500 meters of movement in a lifetime. Because of its unique appearance and living habits, it has become a research object for diving enthusiasts and marine biologists.

It is a unique marine organism belonging to the Syngnathidae family. Mainly distributed in the temperate waters along the southern coast of Australia. The body is slender, with a length of up to 30 centimeters, resembling seaweed in appearance, and has excellent camouflage ability. The body is covered with leaf shaped skin flaps, which not only help them hide in the underwater environment, but also facilitate their swimming in the water. The body color is diverse, usually green, yellow, or brown, and the skin flap often has red or black spots. Feed on small crustaceans such as shrimp and small fish. The breeding method is also very interesting. Males will hatch the eggs laid by females until the small sea dragon hatches.