World of aquarium fish: fish knife

The fish-knife (the family of apteronotovyh) got its name because of a flat, tapering shape resembling a knife. The habitat of these fish is the slowly flowing and overgrown waters of the Amazon River Basin (Bolivia, Peru, Brazil, Colombia). In the aquarium, the apteronotus can reach a length of 30-40 cm, and in nature - 50 cm.

The apterotonus white-crocheted (or black knife) has an elongated body, without scales, with a sharp line of the belly. In the area of the tail, they have an organ that emits weak electrical impulses, allowing the fish to defend themselves against enemies and simultaneously navigate in troubled waters. There are no abdominal and dorsal fins, but the anal well developed, which extends from the head to the tail. By making wave movements with this fin and adjusting them with pectorals, the knife fish can move in any direction, with the same speed (forward-backward as well as up and down). Caudal fin rather small. Color - velvet-black, with a white line running on the back. On the caudal peduncle there are two transverse yellowish-white stripes in the form of ribbons. Female differ from males in smaller sizes and more bulging abdomen. In males, a small fatty cone may be present at the nape.

The black knife is a peace-loving fish, even shy, different in activity at night. A peaceable character, however, is not an obstacle in hunting for smaller fish. A fish-knife is a predator and prey to it, except fish small stuff, tadpoles, worms, crustaceans. Fish of this species live in muddy water and orientate in it, and even at night, they can thanks to electric pulses, as well as receptors located along the length of the body. When moving, the knife fish creates an electromagnetic field that allows it to feel the prey in any direction.

Fish-knife aquarium For its content requires an aquarium from 200 liters and higher with strong aeration, peat filter, water temperature 24-28oC, pH 6-7, hardness 2-10o. They like solitude, so they need personal shelter in the form of snags, zadekorirovannyh tubes or pots. Water replacement should be done once a week, up to 35% of the aquarium volume. White whitened apteronotus is susceptible to ichthyothyroidism. It should be known that in the treatment of this disease, in no case is it recommended to use drugs that contain zinc.

In aquarium conditions, it is desirable to create conditions for fish that are close to natural ones. Between the males there are often skirmishes, so that the shelter for them must be in sufficient quantity. It is necessary to take into account the size of the fish of knives and commensurate with the size of other fish species: small fish they take for food, and too mobile and aggressive neighbors make them uncomfortable. So, apteronotus is absolutely incompatible with barbs, which can cause them irreparable harm by chewing their fins.

Fish-knife Prefers to feed live feeds: insects, tuber, fry of other fish, squid, larvae or shrimp. You can give small pieces of meat. To artificial feeds are accustomed to reluctantly, but with a certain effort to achieve this is quite possible. The best time for feeding fish is towards evening.

Sexual maturity of apteronotus reach at the age of one to one and a half years. For spawning 2 males and 1 female are selected. Spawning usually occurs on a jet of water created by a pump with sprayers (they are specially set for this time), in the morning, in the hours before dawn. Fecundity of the female can reach 500 eggs. Caviar is relatively large, yellowish in color, slabokleykaya. Spawning occurs in crevices between stones, driftwood or scenery. Larvae from caviar appear after two to three days, and after 5-6 days they can already swim and feed on small plankton. From the second month, the fry is recommended to provide a sufficient number of individual shelters, otherwise they can chew the tail stems from each other during a fight.