Tide fish is another name for true octopus and long octopus. Capture in spring or autumn or winter. It is caught by longline fishing. After catching, the internal organs are removed, washed, and used fresh or dried to make dried octopus.

The whole body is brown and the total length is about 80 cm. The head is short and small, with well-developed eyes. There are often small spiny protrusions around the eyes. There is a mouth in the center of the head, surrounded by an oral membrane. There is a horny jaw in the mouth, shaped like a bird's beak. The feet are connected to the front of the head, with 4 pairs of wrists, thick at the base and thin at the tip. The wrists are similar in length, with the lateral wrists being longer and the ventral wrists being shorter. There are many suckers on the inside, arranged in 2 rows; the third one on the right side of the male is The carpal stem transforms into the reproductive arm. The funnel has a cylindrical tip and the funnel is W-shaped. The trunk is oval and connected to the head; there are sparse wart-like protrusions and obvious gray and white spots on the back. Degeneration of shell within body cavity. There is an ink sac behind the mantle.

It lives on the sandy bottom or in the crevices of rocks. It lurks during the day and emerges at night to hunt crustaceans, shellfish and fish.