Celestial pearl danio
Aquarium fish: Celestial pearl danio (Danio margaritatus)
Size: 2.5 cm
Water temperature: 22-27 ° C
Aquarium volume: 30 l
Celestial pearl danio (Danio margaritatus ) – a small, beautifully colored aquarium fish from the carp family. In Poland, it is better known under the original name of Microrasbora galaxy . This attractive species was discovered in 2006 in an undefined part of Myanmar (former Burma) by a Thai ichthyologist and aquarist – Kamphol Udomritthiruj. Due to its small size and beautiful coloration, it quickly became very popular, which started a huge supply, and thus excessive harvest. Which meant that in just 6 months from its discovery, it was close to extinction in nature, and its export was banned.
Fortunately, several new populations have been discovered elsewhere, and commercial breeding has begun on a large scale. First, the species was described in 2007 by Tyson Roberts and included it in a completely new genus Celestichthys. However, at the beginning of 2008, a group of scientists, after careful research, reclassified him to the genus Danio. The initial misname of the species was probably due to a commercial rush, due to the high resemblance to Microrasbora Erythromicron , now also included in the genus Danio. The common name for Celestial pearl danios comes from Latin, where Caelestis means “heavenly” and margaritaus “adorned with pearls.”
They live in shallow ponds, wetlands and puddles stretching along the Salween River, which flows through the mountainous areas of Myanmar and Thailand, and Inle Lake (shallow and heavily overgrown parts of it) – in Myanmar. The habitat where the first specimens were collected is defined as an area of flooded land and ponds caused by human activity (rice production). The water there is clear and shallow, rarely exceeding 30 cm in depth. In addition to rice plantations, it is home to lush vegetation that includes species such as Elodea , Hydrocharis , Vallisneria spiralis.
Characteristics and disposition
Regardless of gender, they grow up to 2.5 cm in length.
Light blue flesh, sprinkled with small pearl dots. Brown-green back and yellow-white belly of females. Gill covers are transparent, with blood red gills showing through. Males are more slender than females. Their fins are bright orange or red, with a black pattern, delicate stripes.
More stocky females have a distinctly less intense body and fins color. The easiest way to distinguish the sex is the dark dot behind the anal fin, which is hardly visible in males. Under stress, the color of the fish fades and it may be difficult to distinguish between the sexes at this time. Danio pearl is a shoal, jumping, very active and curious fish. It shows territorialism towards its species, sometimes you can notice frayed fins, especially when they are in a too small aquarium.
Sexually mature males, and sometimes females (to a lesser degree), compete with each other. They swim around each other, spread their fins, presenting the richness of their coloration. If none of them give up before then, the strikes with the sides of the bodies are exchanged until the weaker gives up and is chased away by the stronger one. It is recommended to keep min. 8-10 pcs, preferably 15 and more, which is important in the predominance of females .
In a large group, the fish will be bolder, nicer colored and show more interesting behavior.
Nutrition and feeding
In nature, they eat small invertebrates, algae and zooplankton. In the aquarium, they eat food from the bottom and the bottom, less willingly from the water surface. You can give them good-quality, fine dry food, preferably the slowly falling one. The diet should be supplemented with small frozen and live foods, e.g.
daphnia, eyelash, artemia, and hydration. More frequent feeding of live food will keep them in good condition, beautiful colors, and encourage spawning.
The minimum size of the aquarium is 30 liters, but due to the high mobility and recommendations for keeping in a large group, a larger tank is preferable. These fish love densely overgrown aquariums with numerous hiding places, preferably with a dark substrate and free space for swimming. The growth of vegetation requires appropriate lighting, initially it must be partially suppressed, e.g.
with floating plants. Over time, in the shade of the lush thicket, they will feel at home. The movement of the water should not be too strong. In their natural environment, they live in slightly alkaline water, approx. 7.3 pH, where its slight changes occur periodically.
In the aquarium, they will feel well in soft to slightly-hard water (5-15 dGH), in the pH range of 6.5-7.5 and at a temperature of approx. 22-27 ° C. Danio margaritatus are very sensitive to higher nitrate concentrations and sudden jumps in parameters . When kept in poor conditions, they often get sick, show symptoms of poisoning, become lethargic and stop eating. They require efficient biological filtration and frequent water changes, avoid sudden changes in parameters.
The first days in a new environment are associated with great timidity. Stressed people stay in the lower parts of the tank. The fish become bold in a larger group or by swimming with other gentle, small species that feed in the upper parts of the water. They can be kept in a correspondingly larger general aquarium with other small peaceful fish with similar environmental requirements and possibly with shrimps. They will hunt for the offspring of shrimps, so the population will be limited.
Although they are closely related to Celestichthys erythromicron , they are not prone to cross-breeding (currently no such case has been reported) and can be kept with it.
Breeding relatively easy, in good conditions, they spread the eggs several times a week. Often in a mature, densely overgrown aquarium, the “galaxy” is multiplied quite by accident. However, in order to obtain more eggs, it will be necessary to set up a separate breeding tank. In such an aquarium, large clumps of moss, approx.
50%, and a small sponge filter should be placed. In the evening prepared in this way, we let the selected couple, the largest female and the most beautifully colored male. Spawning usually takes place in the morning of the next day. The male rushes to the female and then chases her into dense vegetation, where it spawns. An adult female releases about 30 sticky eggs, which the male fertilizes.
Parents do not show parental care and will eat the eggs and fry, so it is best to separate them immediately after spawning. Depending on the temperature, it takes 2-5 days to hatch. A few days later, after their yolk sacs are used up, the fry begin to swim freely. Due to their small size, rearing fry is not easy . In the initial phase, fish should be fed the finest micro powdered and liquid foods, introducing Artemia larvae and micro nematodes as they grow.