About the Pearl Danio
Species Type: Freshwater Fish
Care Level: Very Easy. Will tolerate a wide range of water parameters including pH, temperature and hardness. Can tolerate higher nitrate levels than other fish and is hardy enough to withstand the cycling process. Will readily eat prepared foods and has no special care requirements.
Origin: Native to areas throughout much of SE Asia. Fish from different locales exhibit some differences in colouration and pattern, suggesting that they may simply be colour morphs or they may be a complex of closely-related species. Occurs in small flowing streams, ponds and ditches.
Compatibility/Temperament: Peaceful shoaling fish, must be in a group of at least six; good tankmate for almost any non-aggressive fish such as other danios, smaller barbs, rasbora, characins, anabantids, dwarf cichlids, catfish and loaches. Its adaptability allow it to accompany livebearers and rainbowfishes.
This fish possesses all the attributes of a good "aquarium fish." The scales reflect a beautiful mother of pearl hue under daylight and subdued full spectrum lighting. It will appear "washed out" in sparse tanks, so provide a group of these fish with a well-planted aquarium with a dark substrate and minimal light that can be further shaded by floating plants. Keep the tank covered, as the fish spend a lot of time near the surface and will sometimes jump. Gentle flow from the filter is adequate; these fish, like all the genus, prefer marginal waters that are calm and still.
Females are rounder than males and slightly larger. Spawns easily, and in typical cyprinid manner; eggs are scattered, and will be readily eaten if the adults and eggs are not quickly separated following spawning.
The variation in colour and pattern between fish from different areas may reflect related species or simply variants of the one species. Danio albolineatus was originally described in 1860 as Nurea albolineata by E. Blythe. In 1931, H.M. Smith described a very similar fish as Danio pulcher, and another fish was described as Danio (Brachydanio) tweediei by M.R. Brittan in 1956. This latter fish is sometimes seen in the hobby and literature as Danio kerri. Both of these "species" were subsequently downgraded from distinct species to synonyms of the subject species, but many ichthyologists feel further study is needed to determine if these are or are not distinct species.
In 1991, Talwar & Jhingran placed this species in Brachydanio, a genus erected by George Meyers in the early 20th century when he divided the existing Danio genus into three, Danio, Brachydanio and Daniops. During the latter two decades of the twentieth century, many ichthyologists had doubts about the validity of Brachydanio, and in 2003 Dr. Fang Fang in her study "Phylogenetic Analysis of the Asian Cyprinid Genus Danio (Teleostei, Cyprinidae)" determined that the genus Danio was paraphyletic [Greek para = near and phyle = race], which means the genus contains its most recent common ancestor but does not contain all the descendants of that ancestor. Danio was restricted to the nine species of the Danio dangila group comprised of the smaller-sized species, and the genus name Devario was suggested for the remaining larger-sized species. The former genus Brachydanio was disbanded. The subject fish became Danio albolineatus (Blythe, 1860).
In Joseph S. Nelson's "Fishes of the World" (2006), Danioninae was listed as a synonym of Rasborinae. It is generally held (though some disagree) that there are three clades within the genus Danio, and the danionin genera are within the Sub-Family Rasborinae [having priority over Danioninae] along with several genera of rasborin. The danionins can be classed as a subfamily Danioninae which is increasingly gaining credibility as a distinct subfamily from Rasborinae within the Cyprinidae family. We follow Dr. Fang's placement as the most plausible, though many speculate that the clades may end up as distinct genera.
Pearl Danio Diet
In its habitat this fish feeds primarily on insects at the surface. Accepts most prepared foods, but these should be supplemented with frozen daphnia, bloodworms, small live worms and insects.
Reaches 2.25 inches.
Minimum Tank Suggestion
24 inches in length.
Ideal water parameters for Pearl Danio
Soft to moderately hard (< 20 dGH), acidic to basic (pH 6 to 7.6) water, temperature 20-25C/68-77F. Available fish will normally be commercially raised and thus somewhat adapted to these ranges; wild-caught fish require soft, acidic water.