My biotope aquarium

Common names: Congolese rilčar, tapirjevka

Settlement: Rivers and wetlands - Angola, Benin, Cameron, Central African Republic, both Congo, Nigeria, Zambia

Size: Up to 23 cm

Water chemistry: fresh water. Temperature 23 to 28 ° C, pH 6 to 7.2 (6.8), 3-12 gH (7),

Difficulty: Very demanding (8/10)

Aquarium: 200 liters are enough for a fish, for a group (recommended minimum number is 5 fish), larger aquariums are needed (500 l and more). The aquarium should be well planted with dim lighting. Provide each fish with overturned flower pots, tubes or pits to serve as a retreat. Use fine sand, sand or mud-peat as a base, gravel and coarse sand over 3-4 mm is acceptable. Equip the aquarium with wood and stones. Necessary glass cover to prevent jumping out of the aquarium.

Feeding: Live and frozen food, insect larvae, worms, ... also try flakes. Avoid eating chitin-containing foods too often (crabs, beetles, etc.) because they do not digest it (Occlusion - pathological constipation). Feeding time is best after the lights go out. The reason: they are slow eaters and need a lot of food to stay in good shape, and at night most fish are dormant - resting and not eating.

Breeding: To date, no data. Aquarium breeding has never been successful. One hypothesis on this topic explains that captivity slightly alters their electrical emissions, making them less noticeable. In the case of breeding, the male and female signals are reversed. As a result, fish cannot identify members of the opposite sex.

They noticed that this fish builds floating nests.

Description of fish

It is a school of fish (5+), the species has an elongated, laterally compressed body. The Congolese snout has a small round mouth located above its extension (proboscis), which serves it to search for food on the ground. The dorsal and ventral profiles are symmetrical, and the anal and dorsal fins are opposite. The caudal fin is split. The color is black or black-brown with two yellowish-white stripes extending vertically between the dorsal and anal fins. Lifespan is up to 10 years.

The

Details and interesting facts about fish

Gnathonemus petersii is an extremely fragile fish. Its maintenance is therefore not recommended for beginners (it is not uncommon for only one of two or three fish to survive).

It is very sensitive to water quality, especially nitrates and copper (also pay attention to medicines because they do not tolerate most medicines for fish). The lower jaw ends with a proboscis, this is the most striking feature mentioned in the name itself (rilčar), an extension on the head. It is not a nose, but a sensitive extension of the mouth that it uses for self-defense, communication, navigation, and searching for worms and insects for food, it is a sensory organ.

This fish emits electrical impulses to communicate with its relatives and mark their territory or to search for food. The electrical organ is located in the part of the body where the body passes into the tail, which constantly emits electrical signals and thus a weak electric field around the fish, objects around the fish change it and this is detected by electroreceptors. It has three different types of receptors for receiving electrical signals either from other fish or from the reflections of its own impulses, similar to echolocation in bats.

These are mormyromasts, knollenorgans and ampullary receptors. (electroreceptors are seen in the photo of the head, the largest and brightest dots on the head are knollenorgans, the smaller white dots are mormyromasts, and the smallest ampullary receptors are not visible).

Mormyromasts are organs that sense the echo of a signal. They are the ones that allow fish to navigate in muddy water and search for prey.

Knollen organs detect the weak electrical impulse of other "electric" fish and thus help in communication and finding relatives.

Ampullary receptors measure low-frequency electric fields emitted by other aquatic animals. Similar ampullary receptors are used by catfish and sharks. Knollen organs are tuberous time-encoding electroreceptors, also called communication electroreceptors, found in fish skin, and several hundred electroreceptors have been listed distributed throughout the body surface of the fish, mainly on the head and all the way to the tail.

For its size, it has a fairly large brain, indicating its ability to play and learn, which can be observed in an aquarium. In low light, the fish can see well, although some sources state that it is almost completely blind - this is not true, its eyes use a combination of photonic crystals, parabolic mirrors and have a clustered arrangement of photoreceptors.

Gnathonemus petersii changes appearance and color, from excitement or stress it becomes dark. White bands expand more or less according to the current response to external stimuli. It is a school of fish and it is correct to breed a group of over 5 fish, the fish are territorial to their species, the largest male takes the role of leader.

They need a light current and a strong filter system

The