The White Cloud Mountain Minnow, Tanichthys albonubes, is a small cyprinid native to China. These fish prefer cooler temperatures than most community fish and can be kept without a heater. Despite being one the most common and popular aquarium fish, it is actually critically endangered in the wild and was once believed to be extinct in the wild. All specimens seen for sale are farmed commercially for the aquarium trade; this is the selectively bred 'Gold' strain.
These are adults around 1" long.