What does a zombie fish look like? Analyzing the habitat and species of this prehistoric creature

The zombie fish, also called the eight-eyed lamprey, seven-star fish, etc., is an ancient animal of the class Cyclostomata, order Petromyzontiformes. It does not belong to the same category as the bony fishes of the class Pisces, and is not a fish. So, what does the “prehistoric creature” zombie fish look like? Where does it live? What species are there?

I. What does the “prehistoric creature” zombie fish look like?

The zombie fish looks very much like an ordinary eel, with a slender, eel-shaped body. Its skin is bare and scaleless, and on its back there is a long dorsal fin that extends backward all the way to the tail end and wraps around the tail to form a caudal fin. Apart from this, there are no other fins on its body. There are 2 dorsal fins, the oral funnel is well developed, and there are no oral barbels. The lamprey has only one nostril, located on top of the head between the two eyes. The eyes are well developed, with a pineal eye that has a photosensitive function. Behind the eyes, on each side of the body, there are 7 gill openings, which is why it is called the “seven-gill lamprey.” The inner ear has two semicircular canals. The end of the nasohypophyseal sac is a blind sac. It is dioecious, and its development goes through a relatively long larval stage before metamorphosing into the adult. The adult lives a semi-parasitic life and is harmful to fisheries.

II. Where does it live?

The zombie fish is distributed in the waters of the Arctic Ocean, including the Bering Sea, the coastal waters of Korea, the North Pacific along the coast of Japan, and the freshwater waters of Canada, Mongolia, and Northeast China. Since the Middle Ages, upper-class European society has regarded it as a delicacy.

III. What species of zombie fish are there?

1. American brook lamprey: The American brook lamprey is a non-parasitic lamprey that mainly lives in streams in the northeastern United States. It uses its oral disc to move stones in the riverbed to build a nest for its eggs. Adult American brook lampreys live for about one month and do not feed.

2. Sea lamprey: The sea lamprey comes from the Atlantic Ocean. In addition to building nests with its oral disc, it also attaches itself to larger fish, then uses its tongue to bore a hole in the other fish's body and suck its blood. It will live parasitically on this fish for about two years, after which it migrates to streams to complete spawning.

3. Japanese lamprey: The Japanese lamprey has no outer lateral teeth, and the bases of the two dorsal fins are connected. The total body length of an adult can reach 400-500 mm. Each end of the upper lip plate has one tooth, and there are three pairs of inner teeth, all with two cusps. The lower lip plate has six teeth and a toothed tongue. It is distributed in the Heilongjiang River, the Tumen River, Korea, Japan, and other places.

4. Northeastern lamprey: The northeastern lamprey has outer lateral teeth, and there is a clear gap between the two dorsal fins. It is distributed in the Yalu River, the Taizi River and Hun River, which are tributaries in the eastern mountainous area of the Liao River, the Biliu River on the Liaodong Peninsula, the Hunjiang River in Tonghua, Jilin, the Jiamusi section of the Songhua River, northern Korea, the Russian Far East, and other places.

5. Arctic lamprey: The Arctic lamprey is about 30 cm long and lives in freshwater. Its mouth is cylindrical and has no upper or lower jaws. Its oral cavity looks very much like a human eye, yet is full of sharp teeth. It lives by sucking the blood of other fish, and its appearance has inspired the designs of many monsters in films.