Symbiotic habits of fish

Anchovies often rely on the large suckers on their heads to attach to the ventral surfaces of sharks, whales, dolphins and turtles, and sometimes to the bottom of ships. In this way, it can not only avoid enemy attacks, but also obtain food. While the host is eating other animals, the antoas are able to access food fragments floating on the surface of the water. Sometimes hosts such as sharks only serve as its transport, taking it to a new feeding ground. As soon as it arrives in a school of fish, it immediately separates from its host and goes on a rampage in search of food. After it is full, it will absorb another new host. Sometimes the anchovy will also get into the mouth or gill holes of large bony fish such as swordfish, swordfish and sunfish. It is a kind of pain for parasitism, but it has to be tolerated temporarily. At this time, the anchovy can not only avoid enemy attacks, but also get some food fragments.

Another type of living together is life, where two animals benefit each other. For example, the small tiger scorpionfish in the Indian Ocean is always covered with a group of polyps. The benefits of living together are reciprocal. The polyp group grows on the fish, turning the fish into a stone covered with seaweed, so that it can avoid the harm of enemies, and the fish can bring the polyp group to the bait field to get fresh food.

Fish Parasitism

One type of co-living is parasitism, in which one animal inhabits another animal's body or body, consuming the host's tissues to obtain nutrients. Water lice parasitic on the surface of fish and tapeworms in the body cavity both use fish as hosts. Among fish, there are very few that truly live a parasitic life, and Cyclostome fish are typical fish that live a parasitic life. Lampreys often use their funnel-shaped mouth to adsorb to other fish. The sucker-shaped mouth has a fleshy tongue with polyhedral teeth that can move like a piston. Lampreys rely on this special structure to successfully It attaches to the body of a big fish, tearing its flesh and sucking its blood. The hagfish burrows into the body of the big fish and becomes parasitic in the body cavity of the big fish.

There is a parasitic catfish in South America that lives in the gill cavities of large catfish and other freshwater fish. The parasitic catfish has a slender body that can easily pass through the gill holes of large fish and pierce the host with its sharp teeth and gill cover spines. skin, causing it to bleed, and then suck it with your mouth. The parasitic catfish uses the clustered spines on the gill cover to squirm between the gill flaps of large fish to change its position and find a suitable foothold. In Brazil, this fish often harms local people because it has the habit of getting into the urethra of people bathing in the river. Therefore, both men and women in the local area must wear pants made of coconut fiber to protect their genitals before going into the water. . This small fish usually burrows into the urethra when a person urinates. It is said that the parasitic catfish mistook human peeing as the respiratory stream discharged from the gill holes of a fish.

Another example of parasitism is the horned angler. The male of this fish is very small and spends most of his life parasitizing the female. The female is ten times larger than the male. This special male-female relationship, It seems to have developed to be related to habits and ecology. This kind of fish lives in relatively dark places in the middle and lower layers of the ocean. It moves slowly and lives alone. Therefore, it is very difficult for mature individuals to find a mate. Therefore, as soon as the male hatches, he will immediately look for the female. Once found, he will stay attached to the female for life. There is no fixed location for the fixation of male fish. Some are on the abdomen, some are on the top or side of the head, and some are under the preopercular spines. Occasionally, they can be attached to the side or back of the female fish. The male fish uses his mouth to find a foothold on the female fish's body, and his lips and tongue are connected to the female fish's skin. Finally, they heal completely and the blood vessels of the two are connected. The mouth, jaws, teeth, fins and gills of the male fish, almost all the organs except the reproductive organs, have degenerated. After that, it completely relies on the blood delivered by the blood vessels connected to the female body to obtain nutrients.

There is a small eel-shaped fish called a lurker, which usually lives in the body cavity of sea cucumbers. It does not bring any benefit to sea cucumbers. When the diving fish wants to get into the sea cucumber, it first explores the sea cucumber's anus with its head, then curls its tail and inserts it into the sea cucumber's anus, then straightens its body, and then moves backward until it completely enters the host's body. The body cavity of a sea cucumber can accommodate several divers at the same time. Due to this habit, the diving fish hides in the host's body during the day and comes out at night to find small crustaceans to eat. Not only does the unfortunate sea cucumber gain little benefit from being a host, but its internal organs are also in danger of being damaged.

In Japan, there is a kind of diving fish that parasitizes the body of starfish. This fish sometimes also parasitizes the body of pearl oysters. However, the diving fish that parasitizes the body of pearl oysters is often imprisoned in the shell of pearl oysters. Later, the fish is surrounded by nacre and becomes die. On the coast of the United States, there is a small guinea fish that has the habit of hiding in the outer cavity of a large conch. This fish often emerges from the host body in search of food. Some goby fish live in sponges. These goby fish are small and even in thickness, and can freely enter and exit from the large water outlet on the surface of the sponge body. This kind of fish generally does not have scales, and even if it has scales, they are not well developed, but in Under the lateral line behind the body, there are two rows of large and separated scales. Several long spines grow on the edges of the scales. On the midline of the abdomen behind the anal fin, there are 4 or 5 scales arranged in a row. The goby fish uses this special A structure that can climb up from the stomach water cavity of a sponge. There is a small goby fish that lives in the gill cavity of sprat, slowly bends its body, and then lies horizontally under the gill cover.

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