I traveled from the United States to Lisbon for work in May 2026, then stayed through the weekend with one destination firmly marked on my itinerary: Forests Underwater, Takashi Amano’s immense Nature Aquarium at the Oceanário de Lisboa.
After more than a decade of growth, pruning, maintenance, and slow biological change, the living installation was nearing the end of its run. The Oceanário had announced that the exhibit would close in 2026, bringing an eleven-year experiment in aquascaping to an end. I had followed Amano’s work for years, so finding myself in Lisbon with only months remaining felt like particularly good timing. I wasn’t going to fly home without seeing it.
Walking into the gallery, the room is almost completely dark. Then the illuminated water comes into view, stretching across the space in a sweeping, 40-meter-long composition.
The aquarium contains around 160,000 liters of freshwater. Its construction required approximately 12 tons of sand, 25 tons of volcanic rock, and 78 tree trunks, all carefully arranged to create valleys, slopes, clearings, and dense woodland. It remains the largest Nature Aquarium ever created.
The scale becomes clearer as you begin walking alongside it. One section opens into pale sand and open water. Another rises into thick banks of moss, ferns, and stem plants. Roots reach outward from the planted slopes, creating sheltered spaces where fish gather before drifting back into the open.
It feels remarkably mature. Wood has darkened and softened with age. Moss pours over branches and stone. Plants reach the surface and emerge into the air in places. After more than a decade of careful cultivation, the landscape has the wonderful unruliness of something that has been allowed to grow into itself.
By the time I visited in May 2026, the aquarium was still described as holding more than 10,000 tropical freshwater fish from around 40 species, surrounded by 46 species of aquatic plants.
Altum angelfish move through the taller sections with their long fins suspended beneath them. Pearl gouramis linger closer to the surface and among the roots. A multitude of Tetras stream through the open water while Otocinclus, Siamese algae eaters, and Amano shrimp work their way through the planted landscape.
The vegetation is equally varied. Large masses of aquatic ferns and moss cover branches and stone, while Rotala and Ludwigia create broad sweeps of green, bronze, and red. Lotus leaves reach toward the surface. Plants grow from submerged valleys toward the light, while others cling directly to the enormous pieces of wood that form the skeleton of the landscape.
Takashi Amano and the Nature Aquarium
Takashi Amano was an aquarist, photographer, designer, and one of the most influential figures in modern planted aquariums. Through his company Aqua Design Amano, better known as ADA, he popularized the Nature Aquarium approach around the world.
Amano spent years photographing forests and wild environments in Japan and abroad, including expeditions to the Amazon, Borneo, and West Africa. Those experiences informed the way he approached aquariums. Rocks, wood, plants, negative space, light, and movement could be composed to evoke the structure and atmosphere of a much larger landscape.
You can see that philosophy everywhere in Forests Underwater.
Fish disappear behind planted ridges and emerge farther down the aquarium. Branches create paths through vegetation. Open stretches of sand give the denser sections room to breathe. Light reaches through the surface and catches leaves at different depths. Even areas of open water contribute to the composition.
As someone who spends a lot of time exploring forests, photographing wetlands, and building small ecosystems at home, I found myself studying those transitions as much as the individual plants.
Sand disappears beneath roots. Moss gradually gives way to taller vegetation. Dense shadows open into clear water. From a few feet away, a planted section can look like a single green mass. Move closer and it separates into dozens of textures, leaves, branches, and tiny places for fish to disappear.
I walked around the exhibit several times. Each pass revealed something I had missed five minutes earlier.
Forests Underwater became Amano’s largest and final major work. He led an international team during its creation, working with ADA staff, the Oceanário, and volunteer aquascapers from several European countries. The exhibition opened in April 2015.
Takashi Amano died only a few months later, in August 2015, which adds another layer to seeing the aquarium near the end of its life.
Amano created something designed to live. Plants grew, fish populations changed, wood aged underwater, and thousands of hours of human care kept the landscape moving along the path he originally envisioned.
I left the gallery with hundreds of photographs, although the experience stubbornly resists being contained by a single frame. The length of the aquarium, the darkness of the room, the sound of water, and the gradual accumulation of tiny details all reward moving slowly along the glass.
Beyond the Underwater Forest
Forests Underwater was the reason I extended my stay, but it occupies only one corner of the Oceanário de Lisboa.
At the center of the building is an enormous saltwater aquarium containing roughly five million liters of seawater. The habitat stretches through the heart of the Oceanário and can be viewed from multiple floors, so you repeatedly encounter the same body of water from entirely different perspectives.
Sharks cruise through the deeper water while rays glide overhead. Huge schools of fish continually reorganize themselves into shifting shapes. Around another corner, the same animals might appear twenty feet below where you last saw them.
The architecture makes the central aquarium feel considerably larger than it already is. Rather than standing in front of one giant viewing window, you gradually discover it as you move through the building. Each opening frames another small piece of the habitat.
The Oceanário has become particularly well known for keeping these enormous and wonderfully peculiar animals. Watching one slowly emerge from the blue is an experience. They possess the general appearance of a fish whose assembly instructions were lost halfway through construction.
I also explored the Oceanário’s small botanical garden and planted spaces, filled with tropical vegetation, ferns, and dense greenery.
After spending so much of the day looking at Amano’s interpretation of forests beneath the water, ending the visit among living plants above the waterline felt fitting.
The Oceanário deserves several hours on its own. I went for Takashi Amano and Forests Underwater, then spent the better part of a day wandering through the rest of the aquarium, which is equally as amazing.
