The “penis fish” is a colloquial name for the marine organism Urechis unicinctus, also known as the fat innkeeper worm or spoon worm.
It is not a fish but rather a species of marine spoon worm found in the coastal regions of the Pacific Ocean, including areas like Japan, Korea, China, and Russia.
The name “penis fish” is derived from its appearance, as the creature has a phallic shape, resembling male genitalia.
Urechis unicinctus burrows into the sandy or muddy seabed and is known for its unique anatomy, which has led to its humorous nickname.
In some cultures, particularly in East Asia, the fat innkeeper worm is considered a delicacy and is consumed as food.
It is often used in traditional dishes and is believed to have various health benefits.
However, the term “penis fish” is not a scientific or formal name for the species.