According to Atlas Obscura, the cod tongue is actually a small muscle extracted from the back of the fish. Mammalian tongues are muscular and used for tasting, chewing and swallowing, while fish tongues are bony structures formed by the floor of the mouth to protect the abdominal aorta. The tongue of the fish is located at the bottom of the fish's mouth. A fish's mouth is a fish.

The location of the fish tongue in the fish's mouth, but the function of the tongue may differ from the normal function of the tongue in other animals. The function of the tongue in fish evolved in response to their needs, such as protecting, swallowing, and holding prey, as well as facilitating the movement of water over the gills.
Finally, fish sometimes have teeth on their tongues, fish have taste buds, but they are not on the tongue, but around the mouth. It is unique in that there are taste buds almost everywhere in the fish's mouth, except for the tongue. The presence of taste buds in the mouth is observed in all animals, but the presence of taste buds on the outside of the body is a unique feature of fish.
We often associate taste buds with the tongue, but fish are different. Some fish have a tongue indentation or Basihyal which is not designed for chewing food. In mammals, teeth serve as meat for grinding and chewing food, and not in fish.

Yes, all fish have teeth, but the anatomy and arrangement vary between species. Yes, some fish like salmon, glossanodon and osteoglossomorphs have small teeth in some fish like a salmon tongue. Interestingly, in some species, the teeth on them are not designed to help chew prey, but are actually used to help fish swallow their prey. The teeth on the tongue make it easier to capture fish, scrape meat, and swallow prey.
In addition, the tongue carries hydrogen peroxide through the mouth to the gills, helping the fish to breathe. Typical fish tongues move like pistons, sucking food into their mouths and pushing water over their gills. However, the fish tongue gives the fish the ability to quickly carry food from the front of the mouth to the throat, especially if their tongue is studded with teeth, like a pirarucu. In fish, the function of tongues is to rapidly transport food into and out of the mouth, where in many species one or more additional sets of jaws will grind food.

Humans typically use their tongue to chew food into their mouths, while fish use their tongue to swallow food, pushing it into the back of their mouth to digest it. Brown University supported this idea with a study of how fish and mammals chew differently, describing how many fish use their tongue to push food back into their mouths, while mammals use their tongue to place food in for grinding. Mammals, on the other hand, use their tongue to place food in the right place in their mouth to maximize chewing. Chewing Styles for Different Purposes Fish use the muscles of the tongue to push food backwards, while mammals use the muscles of the tongue to position food for grinding.
In 2008 and last year, Konov and colleagues published papers showing the chewing technique of arched fins, barracudas, and fish with small teeth on their tongues, such as salmon and bony tonguefish (Osteoglossus). Goldfish tongues are similar to other fish with abashjal, a bony structure located at the bottom of the mouth. Instead, fish, including goldfish, have a bony structure in their mouth called a bashial, which looks a lot like a tongue, and is located at the bottom of the mouth, which is their mouth. Betta fish have a thin tongue-like structure in their mouths that they often pull out and lick while feeding.
They have a worm-like tongue and can easily attract the attention of passing fish and prey on them. Like other fish, the fighting fish also have powerful taste buds and are able to enjoy food from afar without even tasting it. All pieces end up in the gills of males, but this may change.

The tongue louse enters the mouth of the fish through the gills, and then with its sharp front claws cuts the blood vessels attached to the tongue. When the host fish dies, the tongue-eating louse separates from the stub of the tongue and leaves the body of the host fish.
Language parasites will remain until the fish or parasite dies. Some researchers believe that a pair of different tongues can, in rare cases, replace the tongue of a fish and help the host swallow food. Not all fish species have tongues, and those that do may lose their tongue to parasites.
The bone-tonguing fish protects the abdominal aorta from the effects of food by swallowing the prey in large or whole pieces. According to a FAQ on the Australian Museum website, the tongue of the fish is formed from a crease at the bottom of the mouth. Many of the tongue-bitten fish that researchers have pulled from the ocean don't look much worse, except for the glowing eyes of the creatures that inhabit their mouths, which "might be a lot less problematic than you might think," Bernot said.