Vladivostok's Hidden Gems: The Invisible Frogs of Primorsky Aquarium
The Primorsky Aquarium in Vladivostok is home to several rare species of Theloderma frogs, often called hole-in-the-tree frogs. These tiny amphibians, measuring just 1.5 to 4 centimetres long, are experts at staying hidden—even in plain sight. In the wild, Theloderma frogs spend most of their lives tucked away in tree hollows, rock crevices, and damp, organic-rich cavities. Their rough, textured skin—covered in strange growths resembling bark, lichen, or bird droppings—helps them vanish into their surroundings. Even trained specialists can search for up to two years without spotting one, despite knowing the frogs are nearby.
The aquarium currently keeps five species: the marbled, starry, Chuangxi, Vietnamese, and brick-red. Yet visitors rarely see them in the display terrariums. A seemingly empty tank might actually hold up to 20 frogs, perfectly camouflaged against moss and bark. Their ability to glide between branches, aided by webbed toes, adds to their elusive nature. Now, these remarkable frogs are used only in the aquarium’s educational project, *Growing Up in the Aquarium*. Children get the chance to observe them up close during one-on-one sessions.
The Theloderma frogs remain one of the aquarium’s most fascinating but least visible residents. Their natural camouflage and secretive habits make them a challenge to spot, even for experts. The educational programme now offers a rare opportunity to learn about these tiny, well-hidden amphibians.
