Nile gymnir is considered one of the most famous freshwater fish in the world. The image of this aquatic animal is found on numerous ancient Egyptian wall paintings in Giza.
In addition to the Nile, the gymnasts are found in the basins of the Albert, Rudolph, Congo and Niger rivers. Large copies constantly generate electrical impulses. The source of these pulses is under the dorsal fin, which operates at a frequency of 300 to 500 hertz and is capable of producing a voltage of about 25 V.
Gymnarchs seem to envelop a weak electric field. The head of the fish has a positive charge, the tail is negative.
Such bioelectric location helps the fish to look for food and find a suitable partner for reproduction.
Gymnarchs have a torpedo-shaped body, flattened on the sides. The back of the fish can consist of up to 130 vertebrae.
The body of the fish is covered with special mucus, anal and pelvic fins are absent. While on the move, the Nile gymnarch looks very impressive and resembles a dragon from fairy tales.
Due to the very long dorsal fin, the aquatic species moves perfectly both forward and backward.
The color of the body of the Nile gymnasium is plain: the body is gray-steel color without any bright spots. The truth was recorded albino forms, body color in which white and pink.
The maximum body length in high school students is about one and a half meters, but, as a rule, there are fish up to a meter in length. Fish become sexually mature after 3 years of life.
In males, the body is more slender, unlike females.
During breeding periods, males construct a large floating nest from pieces of aquatic plants, where the female gymnast can sweep up to 1000 eggs. After spawning, the protection of future offspring lies on the shoulders of the male, who will jealously guard him from any violators.
The incubation period for caviar is about 4 days. After hatching of the larvae, it will take another 5 days for the yolk sac to resolve.
When the bag has resolved, the fry begin to actively feed on the microworm and plankton.
Over the course of a month, the young still maintain external branching forms of the gills, which help the fish to combat oxygen deficiency in muddy water. By the year of life, the length of the body in Nile high schools is about half a meter with good nutrition.
However, due to frequent skirmishes between the fishes, only one fish remains alive in the aquariums.
As you probably already guessed, the hymns are predators that go hunting in the evening and at night. Under the conditions of a hydrobiont aquarium, you can feed on pieces of meat, sea fish, squid meat, tadpoles or dragonfly larvae. The water parameters in the aquarium should be as follows:
- Water temperature 24 – 30 degrees Celsius;
- Water hardness 10 – 15 degrees;
- Active medium reaction 6.2 – 7.5 pH;
- Availability of good filtration and aeration.
The optimum volume of the aquarium for keeping a pair of fish from 300 liters, and the spawn should have dimensions of 3 × 1×1 meters. To protect pets from all sorts of mucosal infectious diseases, fish should be treated with organic dyes or trypaflavinom.
The maximum fixed lifespan of a Nile gymnasium in captivity was 7 years.