Hedgehog fish is an exotic fish that lives in tropical, eternally warm waters of the oceans. He has an unusual ability that he uses for defensive purposes. It is not a commercial fish; hedgehog fish are caught only for making a souvenir. In some countries, a dish of hedgehog fish is served as a delicacy.
Origin of the species and description
Hedgehog fish belongs to the class of ray-finned fish, the order of pufferfish. There are ten families in the detachment, among which one of the representatives is hedgehog fish. The closest relatives are pufferfish, boxfish, and triggerfish. Due to the unique ability to instantly inflate its body, the hedgehog fish was nicknamed the ball fish or porcupine fish. Hedgehog fish belongs to the Diodontidae family, in which there are about 20 subspecies.
The most common of them:
- long-needled diode;
- common diodon (spotted fin);
- black-spotted diodon;
- pelagic diodon.
The family of pufferfishes arose more than 40 million years ago. A distinctive feature of hedgehog fish is the absence of ventral fins, and the dorsal fin is located closer to the tail of the fish, almost on the same level as the anal fin. In fish-hedgehogs, the teeth consist of two hard plates, resembling a bird's beak in shape, with which they are able to grind solid food.
Video: Hedgehog fish
Another characteristic feature of this family is elastic skin with prickly spikes that are located on each of the scales. Hedgehog fish have weak fins, so they are mediocre swimmers. They could easily become the prey of a larger predator, but a special defense system made their life safe.
You need to know this! Some representatives of the Bidentate family are deadly, as their insides contain a deadly poison. It is so strong that even after cooking it remains dangerous. For this reason, if a hedgehog fish gets caught in a fisherman's net, they prefer to throw away the entire catch.
Appearance and Features
It is worth dwelling separately on the features of the hedgehog fish to increase in size and become a prickly ball. Just below the throat, the fish has a special pouch with many folds. In case of danger, she swallows water or air in a matter of seconds, if the fish is on the surface, this bag is filled with water or air, and the fish itself becomes round like a ball. This process has the ability to grow a hundred times its normal size.
The skin of the fish consists of two layers: the outer one is thin and very elastic, and the inner one is folded and more durable. In a calm state, the spines are pressed against the body, and when danger occurs, the skin stretches and due to this they straighten. Ten-day-old fry already have the ability to protect themselves in times of danger.
Outwardly, all hedgehog fish are similar to each other, but if we compare the subspecies of this family, then there are characteristic differences between them. They are mainly distinguished by the size of adults and the location of spots on the body.
An adult long-spined hedgehog fish reaches 50 cm. The fry have brown spots on the belly, which disappear when the fish reaches sexual maturity. In adult fish, the abdomen is white, without spots. There are spots of different sizes near the eyes, on the back and on the sides. The fins of this fish are transparent or with a slight yellowish tint. The long-needled diodon is called a holocanthus, this subspecies is most often chosen for keeping in an aquarium.
The spotted-finned diode also has rather long spines, which makes it look like a long-necked hedgehog fish. It differs from its congener in that the body and fins are covered with many small spots. Even on the belly, if you look closely, you can see barely noticeable spots. They grow up to 90 cm. The black-spotted diode reaches a length of 65 centimeters. Distinctive features of this subspecies are short needles, dark spots with white edging all over the body, two large spots on the face of the fish (near the gill slit and near the eye), dorsal and anal fins are decorated with small spots.
You need to know! The long-spined, spotted-finned, black-spotted hedgehog fish is considered poisonous. The skin and liver contain poison several times stronger than potassium cyanide.
The smallest representative of the hedgehog fish family is the pelagic diodon. In length, his body reaches a maximum of 28 cm. The back and sides are decorated with small spots that are located along the entire body. The fins are pointed at the ends, with dark small spots. There is no evidence that the pelagic diodon is a poisonous fish.
Where does the hedgehog fish live?
Different members of the family diodonons prefer tropical and subtropical climates.
They can be found in the Pacific, Atlantic, Indian oceans, namely:
- Pacific – southern Japanese coast, Hawaii;
- Atlantic – Bahamas, USA, Canada, Brazil;
- Indian – The Red Sea, the coast of India and Australia.
Adult fish prefer to stick to coral reefs, as they serve them in the daytime as a shelter, and at night as a dining room. They can be found at depths of up to 100 m. Unlike them, fry of the diodes stay on the surface of the water, seek shelter in algae and go to the bottom when they grow up.
Of all the subspecies, only the pelagic diodon is not tied to a specific place and prefers to drift with the flow most of the time. Diodons are weak swimmers, they cannot swim against the current, therefore, they are often carried by a strong undercurrent to the Mediterranean Sea or the European coast.
Mostly diodes are marine inhabitants, but some of them have managed to adapt to fresh water, they can meet in the waters of the Amazon or the Congo. Despite the fact that hedgehogs do not often become the prey of other fish, they still settle in places where they can safely hide so that no one bothers them during the day.
What does the fish eat hedgehog?
Diodones, despite their modest size, are predators. Their main delicacy is coral sprouts. Due to the structure of their teeth, they are able to bite off small pieces of coral and grind them. It must be said that only a small part of this food is digested. Most of what was once a coral reef remains in the stomach. In some cases, up to 500 g of such residues were found in the stomach of a diodon caught by fishermen.
In addition, the diet of hedgehog fish is small mollusks, marine worms and crustaceans. If the caught prey hides in a shell or is protected by a shell, it costs nothing for the fish to gnaw through this protection. In addition, diodeons can attack other fish, biting off their fins or tails.
If the diodeon is kept in artificial conditions, the diet includes fish food that contains algae. It must also be possible to grind down your teeth, for this, shrimp are included in the daily diet. Without this treat, the diode can become aggressive, attack other inhabitants, and the teeth will begin to outgrow.
You need to know this! Hedgehog fish do not disdain carrion, and in some cases they can attack their own relatives.
Character and lifestyle features
These fish do not belong to those who prefer to stray into schools, rather, on the contrary, they keep apart and avoid meeting even with their own kind. Only during the spawning period does the male approach the female. Their life goes as follows – the diodeon spends the day in a safe shelter, where he cannot be disturbed, and only with the advent of night does he go hunting. Diodons have developed good eyesight, which helps them find their prey at night.
With such an unusual and effective way of protection, the hedgehog fish could feel safe in any conditions and swim without fear. In fact, they don't like to pout. When the diode uses its protection, it becomes helpless until it returns to its normal state. There have been cases when dead fish were found that could not deflate after the danger had passed.
Despite their unsociable nature, hedgehog fish living in captivity quickly get used to humans and love to float to the surface, begging for a tasty treat. I must say that they do this often, since in the world of fish they are real gluttons. Their large “pug” eyes are often compared to the famous look of a cat from the film “Shrek”.
Social structure and reproduction
Diodons reach sexual maturity at the age of one year. The courtship of the male consists in the fact that he begins to pursue the female. After the female has reciprocated, the male begins to gently push her closer to the surface of the water, where the spawning takes place directly.
After that, the male fertilizes her with milk from his gonads. One female is capable of throwing up to 1000 eggs. Only some of them are fertilized. Immediately after spawning, the fish lose interest in their future offspring, as well as in each other
The maturation of eggs lasts 4 days, after which fry appear from them. From birth, they look like their parents, but at this stage of life, their body is protected by a thin shell. After about ten days, the shell falls off to be replaced by spines. This process takes three whole weeks.
After this time, the fry of the hedgehog fish is already completely similar to its parents, it knows how to inflate itself at the moment of danger. It differs only in a more intense color. Until small fish reach a certain size, they prefer to stick together. In order not to become someone's prey, at the moment of danger they huddle together. At the same time, they become like a large ball with thorns. This scares off the predator.
Until a certain age, small diodes stay closer to the surface of the water, where the water warms up more. Having matured, the fish go to the bottom, closer to the coral reefs, where they lead the usual way of life for the diodes.
You need to know! In captivity, the hedgehog fish is extremely rare, because it needs certain conditions.
Natural enemies of the hedgehog fish
Adult diodeon have practically no enemies, as other predators are afraid to attack him. Only large predatory fish risk attacking them – sharks, dolphins, killer whales. Such cases are isolated. Only for them, diodeon becomes the last meal, it gets stuck in the throat or injures the esophagus, stomach. As a result, the fish dies.
Perhaps, for exotic fish, the main enemy is a person. A favorite pastime of divers is puffing up a hedgehog fish. In addition, diodes are caught for the manufacture of exotic souvenirs. Lampshades or Chinese lanterns are made from them to sell later to foreign tourists.
Hedgehog fish is a favorite delicacy of many peoples and an exotic expensive dish in Asian restaurants. Some prefer to pickle pieces of fish skin in a spicy marinade, others fry pieces of meat in batter.
Fry have much more enemies. From one litter, very few fish survive to independent life. The hedgehog fry are the favorite treat of tuna and dolphins.
You need to know! On one of the Indonesian islands, a tribe made frightening helmets for their warriors from the skin of hedgehogs.
Population and species status
A lot of effort has been devoted to the study of the inhabitants of the world's oceans, thanks to this, the Bidentate family today has 16 species, and only 6 of them are classified as true hedgehog fish. In addition to them, there are other representatives in the Bidentate family: cyclichts, lophodiodons, dicotylichts, chylomicts.
Some believe that the urchinfish and the poisonous dogfish are the same species because they are similar in many ways. This is not true. The fugu belongs to the Four-tooth family, and the diodes belong to the Two-tooth family. Perhaps in the past they descended from the same species, and therefore they can be considered distant relatives.
Appearing many millions of years ago, diodons became permanent inhabitants of the coral reef. If it were not for the unique method of protection, the chances of surviving a defenseless fish at first sight were very low. Only thanks to the ability to inflate, fish to this day are saved from larger predators.
A person could damage the number of diodes, since a certain amount is caught for making souvenirs, importing to other countries, and some of the catch ends up in restaurants. Despite this, ichthyologists and ecologists do not believe that the population is in danger and it is necessary to protect this species.
Hedgehog fish is a funny exotic fish with hooligan manners. It can be seen in many aquariums where you can watch it. Some decide to get this overseas miracle in their aquarium, but for this you need three things – enough experience in keeping fish, a suitable aquarium and create ideal conditions for it.