On September 30, 2026, the world's largest Nature Aquarium quietly closed its doors. "Forests Underwater," Takashi Amano's 40-metre, 160,000-litre tropical-forest layout at the Oceanário de Lisboa, had run for eleven years — from April 2015 to the end of September 2026 — greeting millions of visitors. Originally planned as a two-year temporary exhibition, it became a permanent landmark of the aquascaping world instead. You don't need 160,000 litres to inherit what it taught us: here are five takashi amano forests underwater lessons any home aquascaper can apply to their next layout.
"Forests Underwater" by the Numbers
Before the lessons, the scale — because it shapes everything the tank taught us:
| Detail | Fact |
|---|---|
| Length | 40 metres (the longest planted aquarium layout ever built) |
| Volume | 160,000 litres of freshwater |
| Location | Oceanário de Lisboa, Lisbon, Portugal |
| Opened | April 2015 (built as a temporary, two-year exhibition) |
| Closed | September 30, 2026 — after 11 years on display |
| Livestock | More than 10,000 fish across roughly 40 species |
| Designer | Takashi Amano, founder of the Nature Aquarium style, with a volunteer build team |
Lesson 1 — Plant for the Decade, Not the Photoshoot
Most home aquascapes are designed to peak in three months — right when the contest photo is due — and then they collapse. "Forests Underwater" had to look magnificent in year eleven. That single difference explains almost every plant choice in the layout: slow-growing epiphytes tied to the wood — Anubias, Java fern, Bolbitis, and mosses — that age gracefully instead of stretching, melting, or demanding constant replanting. The background relied on structural, long-lived plants like Vallisneria and large Cryptocoryne types that thicken over time rather than racing upward and then rotting at the base.
The takeaway for your tank: pick species for what they look like in eighteen months, not eight weeks. Fast stems have their place, but your layout's backbone should be plants that hold their form. Learning how to attach aquarium plants to driftwood gives you access to exactly the slow, dependable palette Amano leaned on — epiphytes never need substrate replanting, so they forgive years of maintenance. And when you do include faster growers, plan their maintenance rhythm from day one with our guide to keeping aquascape layouts sharp through trimming.
Lesson 2 — Hardscape Is the Skeleton, Plants Are the Flesh
Stand in front of a photograph of "Forests Underwater" and notice what you're actually looking at: a forest of driftwood "trees" and stone formations. The plants dress that skeleton, but the skeleton is doing the compositional work. In the months when a planting section thinned out — and over eleven years, every section thinned at some point — the layout still read as a forest, because wood and stone held the lines.
Home aquascapers usually do this backwards: they buy plants first and arrange hardscape around them. Flip it. Choose your wood and stone, arrange them into a composition you would be happy photographing bare, and only then choose plants to accent it. The hardscape-first aquascaping method walks through exactly this workflow — rock-and-wood arrangement before a single plant is ordered — and it is the single biggest reason some tanks look composed from week one while others look like a plant sale for six months.
Lesson 3 — Scale Comes from Relationships, Not Size
Forty metres of aquarium reads as a forest not because it's big, but because of relationships: fine foreground textures against broad background leaves, repeating tree forms stepping from tall to short, light and shadow alternating along the length. That is forced perspective and proportion at work — the same tools that make a 60-centimetre tank feel vast.
You can borrow the whole toolkit at home:
- Layer bands of texture. Fine moss and foreground carpet in front, medium leaves mid-tank, broad Vallisneria or Echinodorus behind — the same gradient Lisbon used, compressed.
- Slope the substrate. A rising bed from front to back manufactures depth for free.
- Place focal points off-centre. Amano composed to the golden ratio, not the middle. Our focal point placement rules translate that habit to any tank width.
- Repeat forms, then vary them. Three similar pieces of wood, each a little smaller, suggest a forest receding into fog. The nine depth-creation techniques collect more of these tricks in one place.
If you're working with a genuinely large aquarium of your own, the large-tank scale rules adapt these same principles to 75 gallons and up.
Lesson 4 — Rhythm: Let the Eye Rest Before It Moves
Walk the length of "Forests Underwater" in photos and you feel a rhythm: dense wooded passages, then an open sandy clearing where your eye rests, then density again. The clearings — negative space — are what make the forests feel like forests.
Most beginners fill every gap. Resist it. Plan one or two deliberate resting zones in your layout: an open sand path, a low carpet valley between taller plantings, a stretch of uncluttered water column where schooling fish can actually school. The concave "valley" technique is the classic formal version of this idea, and emptiness used deliberately is a design tool rather than unfinished business. Alternating fine and broad foliage keeps the resting zones feeling intentional.
Lesson 5 — Maintenance Is the Real Masterpiece
Eleven years of continuous display meant thousands of hours of underwater work: divers trimming and replanting, glass polished, filters serviced, and a tireless algae crew — including the Amano shrimp, named after the man himself — grazing day and night. The layout you saw in 2026 was not the layout planted in 2015; it was the 2026 version of a living thing, renewed constantly.
Your home tank obeys the same law on a smaller scale. The aquascapes that look stunning at month twelve are not the ones with the best day-one planting — they're the ones whose owners kept a rhythm: weekly trimming before plants shade each other out, regular water changes, filter maintenance that never slips. If your layout looks great at three months and tired at nine, the problem usually isn't the design; it's the maintenance calendar. New layouts also take longer to "fill in" than social media suggests — set honest expectations so you don't rescape a tank that was simply mid-journey. And if you ever feel the urge to start over, remember that most tired layouts need editing, not demolition.
Apply the Lessons: A Practical Checklist for Your Next Layout
Turn the five lessons into action before you buy anything:
- Sketch first. Draw the hardscape skeleton — tree placements, stone positions, open clearings — before ordering plants, and build your plant list from the sketch.
- Build hardscape you'd photograph bare. If the wood and stone composition holds without plants, it will only improve with them.
- Choose a decade palette. At least half your planting should be slow, dependable species — epiphytes, mosses, hardy background plants — not fast stems that peak and melt.
- Compose off-centre and in layers. One dominant focal point placed to the golden ratio, texture bands from fine to broad, substrate sloping upward to the back.
- Leave the fish somewhere to swim. Open water is part of the composition — and your livestock will behave better in it.
- Hide the machinery. Lisbon's life-support was invisible; yours should be too — keep filters, heaters, and tubing out of the frame.
- Schedule maintenance like an exhibition. Weekly trimming, water changes, and glass cleaning on a fixed day — the layout you want in a year is built one maintenance session at a time.
- Learn the style's grammar. "Forests Underwater" is the ultimate expression of the Nature Aquarium style; understanding its rules for plant grouping and hardscape balance makes every lesson above easier to apply.
Frequently Asked Questions
When did "Forests Underwater" close?
The exhibition closed on September 30, 2026, as announced by the Oceanário de Lisboa's exhibition page. It opened in April 2015 as a planned two-year temporary show, so it ultimately ran for about eleven years — far beyond its original lifespan — and is considered the largest Nature Aquarium layout ever built.
How big was "Forests Underwater" exactly?
The tank measured 40 metres long and held 160,000 litres of freshwater, housing more than 10,000 fish across roughly 40 species. For comparison, that is about 2,600 times the volume of a standard 60-litre home aquarium — yet the composition principles it demonstrated, like layering and focal points, scale down directly to small tanks.
Did Takashi Amano build it himself?
Amano designed the layout in 2015 and led its construction with an international team of volunteers over several days of intensive work. It was one of his final major public works — he passed away later in 2015 — which is why the aquarium's closing feels like the end of an era to many aquascapers.
What plants did "Forests Underwater" use?
The layout leaned heavily on hardy, long-lived species suited to an eleven-year run: epiphytes such as Anubias, Java fern, and Bolbitis tied to the driftwood "trees," mosses softening the wood, and structural background plants like Vallisneria providing vertical rhythm. Delicate, fast-growing stems were largely avoided in favour of plants that age gracefully.
Can I recreate the "underwater forest" look in a small tank?
Yes — the forest aesthetic scales down beautifully. A single dramatic piece of branching driftwood planted with Anubias, moss, and ferns can suggest a full forest in a 30–60 litre tank; the trick is building convincing miniature "trees" from wood and epiphytes rather than planting a crowd of small stems.
Why did the exhibition close after eleven years?
The Oceanário announced that the exhibition was drawing to a close after a decade of display, describing it as the end of a chapter for a living work of art that had connected millions of visitors with tropical nature. Large living exhibitions eventually require complete renewal of their biological systems, and the Oceanário chose to retire the installation rather than rebuild it.
What Takashi Amano Forests Underwater Still Teaches Home Aquascapers
"Forests Underwater" is gone from Lisbon, but its real legacy was never the glass box — it was the generation of aquascapers who stood in front of it and went home to rearrange their own tanks. Amano's great insight was that an aquarium is a landscape first and a container second, and that a layout maintained with patience will outlast any single planting. For more on the philosophy behind his work, explore the official Aqua Design Amano site. The forest closed — long live the forest.