Terence - A fish known to many aquarium lovers, although it is often known under a different name - black tetra. She is popular as a pet because of the relative unpretentiousness, eye-catching appearance and variety of colors. In addition, it gets along well in the aquarium with many other species. All this makes her a good choice for those who are just starting to engage in aquarium fish.
Origin of view and description
The very first creatures resembling fish arose a very long time ago: about 530 million years ago. These were not fish yet, but among such jawless animals like haikouihtis there were fish ancestors.
The fish themselves also appeared about 430 million years ago. Although the species inhabiting the ancient oceans have all died out and have little resemblance to the modern ones, further evolution in basic features has since been traced, and those species were the ancestors of the planet now.
The fish reached their first prosperity after the appearance of the maxillary, the species diversity increased greatly from the Silurian period, and remained at a high level until the Permian extinction. Then most of the species disappeared, and the remaining ones gave rise to a new round of growth of species diversity in the Mesozoic era.
It was then that a detachment of the Characeniformes arose, which included thorns. The oldest extinct Santanichthys fish is 115 million years old. Until the end of the Cretaceous, many other species of the Kharazin variety appeared, but all of them later became extinct.
Most did this during the Cretaceous – Paleogene extinction. But some species remained, and modern ones came from them, including thorns. The earliest fossils of the representatives of the genus Ternetia date back to the Late Miocene, they are about 9-11 million years old, and they were made in Central America.
The description of the species was made by A. Boulanger in 1895, the name in Latin is Gymnocorymbus ternetzi. As aquarium fish, thorns were kept a few decades later.
Appearance and features
Photo: What looks like thornsia
The thorns are small: 3.5-5 cm, but by the standards of aquariums it is even more than average. Their body is flat, wide. Common thorns are silvery, with three dark stripes visible on its sides. Females and males differ little: males are slightly smaller and brighter, their fin is slightly more pointed and long.
The fins are translucent, in addition to the large anal, it is he who secrets the thorns, thanks to him she became so common as an aquarium fish. A small adipose fin is visible just before the tail - it is characteristic of fish belonging to the haracin family.
This fish has this kind in nature, but other color variations were bred for aquariums, and the most varied ones: red, blue, green, orange, lilac - the colors are very bright. As they grow older, the fish gradually become paler, in particular this applies to those whose color is unnatural.
- veil - has large undulating fins;
- gold - painted in a golden hue, without stripes;
- genetically modified - a very bright color, especially under ultraviolet light.
Interesting fact: Although these fish themselves are almost harmless, the bloodthirsty piranhas are their close relatives, they belong to one group of haracyniformes, as evidenced by the external similarity between these fish.
Now you know how to care for thorns fish. Let’s find out where they live in the natural environment.
Where does thorns live?
Photo: thornsia fish
In nature, this fish can be found in South America, in Brazil and Paraguay.
It inhabits the basins of several large tributaries of the Amazon, such as:
- Rio Negro
- Paraiba do Sul.
For thornsia, unhurried plain rivers, abundantly overgrown with vegetation, are preferred. This does not mean that fish lives only in large rivers: it lives in small streams, and even streams - the main thing is that they are not too fast.
The water in such slowly flowing bodies of water is soft, in addition, it is quite acidic - and thorns very much prefer this. They also love shady areas, and you can usually find them in a reservoir in those places that are next to trees, in their shade. Prefer rivers with dark water rather than clear.
They usually swim in the upper layer of water, where it is easier to find their preferred food. In the aquarium, they can swim in any layer, and when they are kept, to ensure the comfort of the fish, the main thing is that there should be more plants, and in the middle there is a zone for free swimming.
Fish came to Europe in the 1930s and quickly spread widely among aquarium owners. This was facilitated by the fact that the thorns easily tolerated captivity and multiplied in aquariums.
What does thorns eat?
Photo: Female of thornsia
In the natural environment, the basis of nutrition of this fish:
- their larvae.
- small crustaceans.
Typically, the reservoirs in which the thorns live abound in this kind of food. Moreover, this fish is unpretentious and not particularly picky in food: it can eat almost any small liveliness that it can catch. The food of animal origin predominates on its menu; accordingly, it should be fed in the aquarium.
She can be given both live and frozen food, the fish will be happy to eat daphnia, brine shrimp, bloodworms. The feed prefers to be taken at the very edge of the water or in the middle layer, because of the location of the mouth from the bottom it does not raise it. If you give a lot of food at once, the fish can overeat, and constant excess of the norm will lead to the fact that they are overweight.
Given this, it is preferable to give them such food that will sink to the bottom slowly, while strictly dosing it. Then the fish will eat everything and the bottom will not be clogged. The throne itself is undemanding, but it should be remembered that it must be fed in a balanced manner, you can not give the same day after day.
Dry feed should be mixed alive, to introduce a few components of plant origin into the diet. If the thornsion eats too monotonously, it will begin to hurt more often, it will multiply worse, disturbances in fish metabolism are possible.
Suitable for it are many mixtures sold in stores intended for tropical species. Feed options containing natural dyes will be useful - eating them, thorns regains its former brightness. Fry and only individuals transferred to a new aquarium need vitamin supplements.
Features of character and lifestyle
Photo: Male of thorns
In wildlife, thorns prefer small rivers or even streams, live in small flocks of 10-20 individuals, and behave very actively, constantly hunt, scare smaller fish and can even attack each other.
Most often, such attacks do not end with serious injuries, both opponents remain in the pack and cease to conflict; however, sometimes only for a while. From predators, thorns swim away in different directions, after which they gather again only when they are satisfied and stop hunting.
In an aquarium, the behavior of the fish largely depends on its volume. If it is spacious, then thorns usually float in the middle layer and spend most of the time in free water. If the aquarium is cramped, they behave very differently: they mostly hide behind plants, but go out only to eat.
For thorns, an aquarium of at least 60 liters is required, it must have soil and plants. This volume is enough for ten individuals. The aquarium is required to be well lit and its water temperature slightly above 20 ° C. Water change should be carried out once every two days, 30-40% of its total volume should be updated per week.
With other fish, thorns get along well, although it depends on their species. It is best to keep it together with other characins, pecilia, guppies. Unfriendly to small or veiling fins. The thorns themselves should be at least 3-4, and preferably 7-10, if only one fish of this species is placed in the aquarium, it will be aggressive towards its neighbors.
The same applies to flocks that are too small. With a normal population, the attention of the fishes is mostly occupied by fellow tribesmen, they spend most of the time with each other, and even if fights arise between them, they practically do no harm. In such a flock of fish will have fun frolic and delight the eye.
The soil in the aquarium should consist of sand or fine gravel - as in its natural habitats. At the bottom, you can put several small snags. It is best to dim the light, you can do it with plants floating on the surface - this will also create an atmosphere close to the one in which the fish live in nature.
It is highly desirable to enrich the water with oxygen, it is also useful to use one of the conditioners that create the effect of "dark water". If you do all of the above, the thorns will feel as if at home in the aquarium, although the fish are unpretentious, so compromise options are possible.
Interesting fact: Aquarium with thorns must be covered, because they are able to jump very high, so they can even jump out of it.
Social structure and reproduction
Photo: Colored thornsia
Although the flocks of thorns are small, a hierarchy is created inside them, there are frequent fights in which the males find out who is stronger and will use the priority attention of the females. Fish do not get serious wounds in such fights, so you can ignore them. In an aquarium, it is preferable that they spawn in pairs, although flock spawning is sometimes possible. For spawning, a special aquarium designed for 30-35 liters is used. It should have very warm water: 25-26 ° C, hardness should be 4 dH, and acidity 7.0 pH.
Before spawning, preparation is needed: males and females are seated and kept separately for a week, giving them high-protein food. At first, only the male is placed in the spawning ground, and only after two or three hours does the female add to it. The aquarium should be in the shade, and at the beginning of the next day it needs to be highlighted. At the bottom of the spawning grounds there is a nylon mesh with cells wide enough for the eggs to pass through them, but too narrow for the fish to reach it. Spawning does not always occur on the same day, sometimes it may not start for several days. To speed up the start in such cases, fish are fed with bloodworms.
One female spawns from 500 to 2,000 eggs in several stages, the process lasts for hours. Until it ends, the fish do not touch the eggs, but after the end they can try to eat it. Therefore, when spawning ends, they are immediately sent back. In spawning, the water level must be reduced to 10-12 cm. From spawning to the appearance of larvae, a day and a half pass, the larvae at first simply hang on plants or glass. They develop very quickly, it takes only 4-5 days to turn into fry, that is, begin to swim freely.
Only then can they be fed. They are given ciliates, nauplii brine shrimp and special food. At first, the food should be very small, and it should be given in small portions. Over time, servings should be increased, enlarging the feed itself. Fry can eat each other. To prevent this from happening, it is advisable to sort them by size and plant them in different aquariums. Fish become sexually mature after they pass for six months, sometimes only by 9-10 months. They can multiply until they reach the age of 2-2.5 years, live 3.5-5 years.
Natural enemies of thorns
Photo: What looks like thornsia
Enemies in nature in thorns are common for small fish: they are larger predatory fish and birds. Although for the most part thornsia live in small bodies of water, where large fish are not so common, but sometimes it can be visited just for prey. In such cases, thorns can only flee.
But the rest of the time, they themselves often turn out to be the main predators, because the other inhabitants of the small rivers where they live are even smaller. In such cases, birds become their main enemies, because it is not so difficult for them to get a small fish out of a small river, and hiding from feathered predators will not work out.
Large rodents and cats can also pose a danger to her, which sometimes can try to catch fish, because the thorns often stay in shallow water near the shore.
People do not care much about them: thorns are successfully bred in aquariums, and therefore they almost never catch new ones, especially since these fish are cheap. They live in underdeveloped places in the thick jungle of the Amazon, so that human activity has almost no effect on them.
They are subject to relatively few diseases, and this is another plus of their content in the aquarium. Still, problems are possible: they can become infected with a fungal infection, about which a white coating on the body will speak. If infection has occurred, the diseased fish should be deposited and treated, and the aquarium should be disinfected.
Population and species status
Stock Foto Green thorns
The range of thorns remains almost unchanged from the moment of their discovery; it even expanded slightly due to the introduction of this fish by humans into bodies of water adjacent to its habitats. No disturbing signs were found, nature in those rivers where this species lives has so far almost suffered no damage from human activity, so nothing threatens thorns.
There are no exact data regarding their total number, no calculations are being made. However, it seems that it remains at the same level, or even grows. Although the range of thorns is not very large, and they live on only one continent, the territories on which they are inhabited are very densely populated.
In the basins of the large tributaries of the Amazon and Paraguay, this fish is one of the most widespread, and you can find it everywhere. Among small fish, this species may become dominant and displace others from the best territories. They multiply rapidly, so the flocks sometimes have to share, some go in search of another backwater.
Interesting fact: It is advisable to keep them in the dark, because otherwise they will fade much faster than usual. This applies to both natural thorns - from dark ones they gradually become more pale gray in the light, and bright - they will quickly fade. Their color also fades due to stress, for example, transportation or transplantation, in which case its brightness can recover over time.
Terence - A frequent choice for aquariums, because this fish combines beauty and durability, so keeping it is quite simple, and even inexperienced owners of aquariums can safely start it. In addition, it gets along well with many other species, so you can keep it in a common aquarium - but you need to start a whole flock and allocate more space.