Among the huge aquarium diversity, one of the most interesting is the fish, known as the "black knife". Officially, she is called afteronotus, and in English-speaking countries her name is "black ghost." Aquarists with experience willingly bring such an exotic to their glass pools. But beginners, perhaps, need to gain experience before daring to make such an acquisition: a black knife is a fish, the content of which requires special attention and skills.
Where did the apteronotus come from?
This exotic fish is home to the South American continent, where she mastered the expanses of Peru, Brazil, Bolivia, Colombia - the top and middle of the Amazon. And in Paraguay a black knife is found in the Parana River. He prefers water bodies with a weak, unhurried course and rich underwater vegetation. The waters in such places are cloudy, their visibility is very low. Therefore, afteronotus has very low vision, but there is an alternative way of navigation - weak electrical impulses, the source of which is white rings covering the tail. In nature, the black knife protects them from attack and seeks food. The ateronotus appeared in aquariums very recently - only about twenty years ago. But I already managed to make fans for myself.
Appearance
In the home "pond" aquarium fish "knife black" can become its decoration. Smooth, soft outlines and plastic movements even in people who are indifferent to the aquarium, immediately attract attention. Athertonotus grows to fifty centimeters (unless, of course, it has enough space). The absence of scales gives the impression that the fish is velvet and makes its color deep and soft. The back fin of the fish is absent, but the anal stretches along the entire abdomen. Thanks to this structure, the black knife can swim in any chosen direction, adjusting its movement with pectoral fins. A very common phenomenon is when the apertonotus floats on its side. If a person before that had only other fish in which such behavior indicates an unhealthy condition, the aquarist may suspect something was wrong. But for knives, this style of swimming is an ordinary occurrence.
We equip a new home
If a black knife caught your attention, its maintenance will be successful only in a large aquarium, not less than 150 liters in volume. The lack of space will not only prevent it from growing to the extent possible, but it will also undermine health, weaken the immune system and make it more vulnerable to various ailments. The temperature should be maintained at 23 degrees; by reducing it to indicators less than 18, you are guaranteed to lose your pet - the fish is tropical, thermophilic. A third of the water needs to be changed weekly. Moreover, the aquarium should be equipped with a reinforced aerator and a peat filter. “Landscape” is made out by numerous shelters: a black knife is a creature of the night, it hides during the day, and there should be enough space for this. As for lighting, it is needed more for underwater plants, since the activity of the apertonotus is only at night, and his vision is poor. It is worth taking care of the glass cover on the aquarium: there are cases when black knives jumped out of the water.
Nutrition
In vivo, the black knife fish feeds on fry of other fish species and insect larvae, that is, it is carnivorous. At home, it is fed with live or frozen food: tubule maker, bloodworm. Quite willingly, a black knife eats crumbled shrimp and squid. Dry food, like any substitutes, is ignored by the fish until it is finally starved. In principle, they can be accustomed to such a diet, but not practical. Feeding is done once a day, after turning off the aquarium lights. Aperonotuses often die from overeating, so you need to calculate your pet's norm and give a little less.
Who to let in the neighbors
In principle, the knife is black - the fish is peaceful and non-aggressive. Skirmishes occur only between males of a kind in territorial disputes. However, given the predatory nature, it is better not to attach small fish like neons and guppies to the apertonotuses: they will eat. To larger neighbors knives are absolutely indifferent. However, it is better not to let too moving fish - for example, barbs - into the same aquarium with them. Athertonotuses are shy, and from excess movement around can get stress. In addition, such neighbors can pat the thin fins of black knives.
Regarding health
Since the black knife is devoid of scales, it is especially vulnerable to ichthyophthyroidism. Its treatment is complicated by the fact that categorically it is impossible to use drugs that contain zinc, so when buying medicines you need to carefully read what is in their composition. Signs of the disease are:
- white small tubercles from half a millimeter to one and a half in diameter. Aquarists call such a rash semolina;
- frayed or stuck together fins - the sign is already secondary, showing that the process has gone quite far. Moreover, such a symptom is also characteristic of other diseases;
- body swelling. Also observed with various diseases.
Ichthyophthyroidism in other fish species is often treated by salting water in an aquarium. But the black knife may die from such measures. If you want, you can search for any proprietary products. However, it has been verified by many - rather malachite green. It is harmless to plants, does not impair biofiltration, so you can safely bring it directly into aquarium water. The usual concentration for the treatment of ichthyophthyroidism is 0.09 mg / l. However, given the absence of scales in the apertonotuses, it should be reduced to 0.04 mg / L. The product is added to the water daily, before each introduction a quarter of the water in the “pool” changes, and this is done until the “semolina” disappears plus two days after that.
Black knife reproduction
Afteronotus is a viviparous fish. Breeding it at home is quite difficult and rarely successful. However, you can try. For this, the selected pair is placed in a spawning tank with a volume of 100 liters; water temperature should be stable 25 degrees. At the same time, you constantly need to add a little clean water - this is an imitation of the rainy season. Plus, provide a stream of water in which caviar is deposited. At the end of the spawning, the parents are removed from the spawning. After 2-3 days, the fry hatch. All this time, you need to monitor the situation in the aquarium and remove dead eggs.