Not to be confused with the smaller Celestial Pearl Danio (Danio margaritatus), the Pearl danio, Brachydanio albolineatus, is a mid-sized species of Danio that reaches a little over 2". These highly active schoolers are usually quite drab when first bought, but with maturity they develop shimmering purple iridescence over the whole body. It may be an exercise in patience waiting for the dull juveniles to grow into beautiful adults, but the spectacle of a mature group of these fish swimming through a tank is well worth the wait. Like most other Danios they are very hardy and peaceful, and should be kept in schools (5-6+ is ideal).
These are subadult specimens around 1-1.25" long.