A Blue Poison Frog (Dendrobates azureus) shot through glass at the Tropical House, Copenhagen Zoo. Info [link] :
Dendrobates azureus is a mid-sized dendrobatid frog weighing about 3 grams and having a length ranging from 3 to 4.5 cm. Dendrobates azureus is brightly colored, and this coloration serves as a warning to would-be predators of its poisonous properties. In fact, its skin is covered with a myriad of glands that secrete alkaloid poisons capable of paralyzing, even killing predators. The coloration of D. azureus is an azure-blue hue on the limbs, a sky-blue on its dorsal surface, and a darker blue on its ventral surface. An irregular pattern of dark blue and black spots of various sizes cover this background coloration with the majority of the spotting located on its back as well as head. The pattern of spots is unique to each frog and thus serves as a "fingerprint" to differentiate between individuals.