Aquarium fish: Danio rerio (Brachydanio rerio)
Size: 5 cm
Water temperature: 18 – 24 ° C
Aquarium volume: 54 l
Danio rerio (Brachydanio rerio ) – freshwater, characteristic and very popular in aquarium fish from the carp family.It also serves as a model organism in vertebrate development research.
The fish comes from Asia . This very widespread species lives in streams and smaller rivers, as well as stagnant waters, irrigation canals and flooded rice fields in Pakistan, India, Bangladesh, Nepal and Burma.
Characteristics and disposition
Slender characteristic fish growing up to 5 cm. It has silver or gold coloration with blue or purple stripes along the body, running from the head to the outer edge of the caudal fin, sometimes reaching the anal fin.
Males are a bit smaller, slender and more intensely colored than females. In addition to the wild form, there are also breeding forms with very long fins, the albino. Danio leopard (spotted) is a mutation that can also occur in nature. Danio red, green, pink, fluo (fluorescent) etc. are genetic varieties.
The breeding forms are usually more sensitive than the very hardy base forms. Danio is a beautiful, energetic and calm school fish at the same time. It inhabits the middle floors of the reservoir. He feels best in a herd of 8-10 individuals. Especially recommended for beginner aquarists.
Nutrition and feeding
We feed the fish with dry food in flakes or granules, supplemented with frozen or live food, e.g. daphnia, artemia or hydration, as well as plant foods with the addition of spirulina. A balanced diet will keep them in good condition and beautiful coloration.
For a small group of about 8-10 individuals, an aquarium of 60 cm in length is sufficient, with a fairly strong, forced current of water, richly planted with vegetation, but at the same time with a large space for swimming. They are an excellent species for long and flat aquariums .
The fish look best in a tank with a dark ground and not too strong lighting. A covered aquarium is recommended due to the taste for jumping out of the water. In a general aquarium they can be kept with gentle species of similar size and environmental requirements, e.g. other carp, bites, kiryskami, bots, catfish, etc.
Breeding of this species is relatively easy.
An aquarium with 40 liters of water is best filled with soft or neutral water. The water temperature in the aquarium should be between 24 and 26 degrees. Glass balls, fine mesh netting or a large amount of moss (e.g. Javanese) will be suitable for the bottom. Place the aquarium on the windowsill of the eastern window – so that the first rays of the sun fall on them.
Several days before spawning, the fish are separated by sex and fed copiously, preferably with live or frozen food. For spawning, we stimulate a larger change (40%) of fresh, slightly cooler and well-oxygenated water. The upcoming spawning time is evidenced by the female’s enlarged, filled with eggs, belly, the restless behavior of the males and the general, increased activity of the fish. The selected pair is placed in the spawning tank in the evening, usually the next day spawning takes place. In courtship, a more active male vigorously flows around his partner, stretches his fins in front of her, and sometimes gently slaps his mouth on her lower abdomen.
Courtship is preceded by constant chases. If the female is ready for breeding, the partners hide in a thicket of plants where the male hugs the female and after a short flapping of the spawners, the eggs are scattered and fertilized. The female lays 4 to 12 pale pink eggs with a diameter of 1.2 mm. This act is repeated many times until the stock of mature eggs is exhausted. Depending on the age, the female lays between 200 and 1,000 eggs.
All zebrafish species produce non-sticky eggs that fall to the ground. After spawning, the female is usually thinner. If the fish do not precipitate, we catch them and repeat the procedure with another pair. Adult specimens eat their eggs, so it is necessary to catch them. Hatching takes place within 2 days.
When the larvae begin to swim freely, we feed them with micro food for the fry, and after a few more days, live food, e.g. artemia larvae or micro nematodes.