SCIENTIFIC NAME: CELESTICHTHYS MARGARITATUS Danio margaritatus, the Celestial Pearl Danio, often referred to in the aquarium trade as galaxy rasbora or Microrasbora sp. 'Galaxy', is a small cyprinid from Myanmar. It has been found so far 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. On February 28, 2007, Tyson R. Roberts of the Smithsonian Tropical Research Institute released his formal description of the species, erecting a new genus for it. He also suggested a new common name, since his discovery of a familial relationship between this fish and the danios meant the trade name galaxy rasbora was misleading. Dr. Roberts coined the common name of Celestial Pearl Danio to reflect that the fish are actually danionins, related more closely to the danios than to the rasboras. Males of the original fish are a deep midnight blue overall, with a series of pearlescent spots over their flanks, sometimes arranged in rows. Their unpaired fins have bright red stripes outlined in midnight blue. The ventral fins are solid red, or are filled with red splotches or spots. The males also show a bright red belly, and dominant males, reminiscent of male rainbowfish, are reported to flash a red stripe on their backs that runs from the top of the head to just before the dorsal fin. In contrast, the female is more subdued in overall coloration and has a rounder body. In their homeland, Celestial Pearl Danios are found in a series of groundwater or spring-fed ponds in the Shan Plateau where the Salween River cuts a deep swath. It is important to note that the fish occurs in several ponds, not just one as has been widely reported. The area is mostly grassland and rice paddies, so the ponds are open to the sun and filled with a rich variety of aquatic plants. The Celestial Pearl Danio has evolved to take maximum advantage of this, and hobbyists should strive to remember their native habitat when setting up a tank at home. At an adult size of about ¾ to 7/8 of an inch, including the tail, the Celestial Pearl Danio seems perfect for the popular desktop tanks or nano tanks, but only one male can be kept in such a small space. A tank of 10 gallons or more would be perfect for a group of them to best recreate the natural habitat with rocks, driftwood, and ample plant cover. In a larger tank you really get to see some of their interesting group dynamics, and subdominant males have a place to get away. The Celestial Pearl Danio is an omnivore that will eat commercially prepared flaked foods and algae as well as freeze-dried daphnia, bloodworms, tubifex, and brine shrimp.
