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Danio margaritatus


Danio margaritatus
Celestial Pearl Danio
火焰珍珠斑马
The Celestial Pearl Danio, Danio margaritatus - often referred to in the aquarium trade as galaxy rasbora or "Microrasbora sp. 'Galaxy'" - is a small cyprinid from Myanmar. It has so far been found only in a very small area near Hopong east of Inle Lake, at an altitude of over 1,000 m (3,400 ft). Its habitat is part of the Salween basin, namely the Nam Lang and Nam Pawn rivers. Discovered in 2006, the species quickly appeared in the aquarium trade, where its small size and bright colours made it an instant hit.this is a small plump danionin with a markedly blunt snout, measuring just 1.5–2 cm standard length. The body is about three times as long as it is high. In general shape, it resembles "Microrasbora" erythromicron more than any other known species. This species shows some sexual dimorphism: males have a bright blue background color (dull blue-green in females), and their fins are more brightly colored. The tail end of their bodies (the caudal peduncle) is also higher than in females. The body is sprinkled with small, pearly dots. The back is bronzy green, and the belly in females is yellowish-white. The gill covers are transparent, letting the blood-red gills shine through.

The males' fins (except the pectoral fins), which they will prominently display to conspecifics, show two parallel black lines with a bright red area in between; on the tailfin this pattern is present twice (once on each lobe) and the outer black band is vestigial. Females have a weaker version of the pattern in the tail and dorsal fins only, sometimes in the anal fin too.
Courting males develop a red belly and the flanks brighten and darken, making the pearly spots stand out even more, with the back appearing paler than the flanks and also standing out. Females in reproductive age can be recognized by a black anal spot which separates the belly color from the uniformly reddish base of the anal fin. Males have a small black pad at the edges of the lower jaw, which is absent or reduced in females. Immature fish show some indication of a striped pattern, which eventually decomposes into the pearly dots. Initially Danio margaritatus was thought to be a member of the genus Microrasbora and was traded as such. This was assumed because of its similarities with "M." erythromicron, which almost certainly does not belong into that genus and appears closer to Danio. Less than a year after the discovery of the Celestial Pearl Danio, it was scientifically described and given the genus name Celestichthys. This once again raises the issue of where "Microrasbora" erythromicron should be placed; it was noted that including it in Celestichthys might seem plausible at first sight, but probably would not correctly represent these fishes' evolutionary relationships. In 2008 further a study including DNA testing placed the species in the genus Danio as the study discovered that it was more closely related and more similar to other "Danios" than Tyson Roberts study had shown. Tyson Roberts didn't DNA test this species in his studies. The fish lives in small ponds created by seeping groundwater or overflow from small brooks or springs. Water temperature in January was rather low (22-24°C), but as the habitat is very shallow, it would heat up quickly during hot spells and thus D. margaritatus is probably tolerant of temperatures in the low to mid 20s. Like most waterbodies in the Inle drainage, the water is slightly alkaline. The habitat is heavily vegetated with Hydrocharitaceae similar to Elodea (water weed).
The Celestial Pearl Danio shares its habitat with very few fish species. Namely, a Microrasbora similar to M. rubescens, a rosy loach (Yunnanilus, possibly a new species) and the dwarf snakehead Channa harcourtbutleri. The latter species presumably is the only known significant predator of D. margaritatus.

The Celestial Pearl Danio is a rather undemanding fish if its basic requirements are being taken care of. It seems quite hardy but obviously thrives best in fairly soft and slightly alkaline water at not too high a temperature - conditions that can often be met with pretreated tap water. It does not require much space, as it is not a very active swimmer, and is not a true shoaling fish, meaning it does not require large numbers of conspecifics for its well-being. In a small tank, a group of 6 individuals - half males, half females - will do well and exhibit natural behavior. They tend to be rather stationary, hovering in a peculiar position in favorite spots; males and females tend to keep separate when at rest. Altogether, their behavior again resembles "Microrasbora" erythromicron more than other fish.

Tanks for the Celestial Pearl Danio should be well-planted and direct daylight may be favorable (the natural habitat is so shallow as to be well lit throughout). Water weed and similar plants should be abundant, and stones and wood to create hiding spots should be provided. It is advisable to supply the fish with a spawning mop or a dense growth of suitable plants (java moss has been successfully used). A dense tangle of natural plants for spawning has the additional advantage of harboring protists on which the fry feed initially. The Celestial Pearl Danio seems overall quite peaceful, though some fin-nipping occurs. Consequently, it cannot be accompanied with large or "bully" fish. Small, swarming danionins which require similar water conditions would be a natural choice for company, as such more active species provide nice contrast behaviorally and, being available in a wide range of colors and patterns, also make it possible to choose fish that complement the brilliant colors of D. margaritatus. Note than many danionins prefer slightly acidic water however, and that maintaining the rather high pH found across the Inle basin seems a necessary condition to keep fish from there successfully.

火翅金钻灯的原生地,距离缅甸境內第二大高山淡水湖泊---茵列湖,火翅金钻灯正式被美国的鱼类学家 Tyson Roberts 博士所鉴定。让人惊讶的是牠不仅仅是个新物种,还拥有一个新的属別「Celestichthys」,同时也是目前该属唯一的品种,全名为「Celestichthys margaritatus」;其属名和种名有著异曲同工之妙,都是在描绘、刻画出牠们是一种「身上镶嵌著如繁星般的珍珠」之鱼种。回想起来,这个名字也似乎是「名符其实」,火翅金钻灯无论是在身形、体色、斑纹等表徵上都算是「一枝独秀、自成一格」
特性:背鰭、腹鰭及尾鰭為紅黑相間的斑塊,金黃色小圓斑點佈滿黑色底色的體表,猶如一塊黑布上鑲著小小黃金,水質穩定時,紅色表現出鮮紅的美麗色澤,野外最大體長約1.5 cm,人工飼養下可達3 cm。適應性強,不挑食,幾乎所有燈科魚能吃的食物它都能吃,易於飼養。性情溫馴,水質為弱鹼性,適合群泳及與其他小型魚混養,建議一次飼養5尾以上。火翅金鑽燈的雄魚好鬥,地域性相當強,對其他雄魚忍耐力和包容性低,雌雄魚交配的時候會貼的很近,大力抖動身體後一同鑽入默絲推中產卵,卵的黏度不高,輕輕碰就會滑落。火翅金鑽燈有食卵性,玩家可以裸缸方式把種魚養在一個魚網縫製的大型方網中,授精的卵就或掉落到缸底,在取收出來即可。受精卵是溫度而定,一般是2-3天孵化,一開始用蛋黃水或是極細的粉末飼料,14天後可用無節幼蟲,大約3個月後就成魚了,可以再次繁殖。
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