Do you know that Yamanashi Prefecture has only one aquarium?
The Yamanashi Prefectural Fuji Spring Pond Aquarium, also known as “Mori no Naka no Suizokukan” (Yamanashi Prefectural Fuji Yusui no Sato Aquarium・Aquarium in the Forest), is a rare freshwater-only aquarium that showcases the beauty of life sustained by Mt. Fuji’s pure spring water.
Inside, you’ll find around 100 species and over 10,000 freshwater creatures—making it a paradise not only for fishing enthusiasts but also for beginners and families.
Because it’s an indoor facility, it’s an ideal destination for rainy-day sightseeing. In addition to the aquariums, visitors enjoy detailed explanations and fun, witty comments written by the staff, making every exhibit both educational and entertaining.
Since its opening in 2001, the aquarium has been dedicated to sharing the beauty of Yamanashi’s nature and aquatic life. Whether you’re deeply passionate about fish or simply looking for a unique spot to explore, Mori no Naka no Suizokukan is a must-visit destination.
In this article, we’ll dive into the highlights and must-see points of Yamanashi’s one-and-only aquarium!
Double Circular Tank
One of the highlights of Mori no Naka no Suizokukan is its Double Circular Tank, an oval-shaped giant aquarium with a fascinating twist. At first glance, it looks like a single tank where large and small fish swim together, but in reality, it’s cleverly designed with a two-layer structure.
- In the outer tank, you’ll see large fish such as Ito (Japanese huchen) and rainbow trout gliding gracefully.
- In the inner tank, smaller rainbow trout species and juvenile fish swim about energetically.
This unique setup allows visitors to observe the interactions and behaviors of both large and small fish at the same time—a rare experience you won’t often find elsewhere.
On the lower basement floor, there’s also a walk-through underwater tunnel where around 3,000 fish surround you in all directions. With a full 360-degree view, it feels as if you’ve stepped right into their aquatic world.
This spot is especially recommended for families, couples, and anyone with a love for fish and nature.
Deep-Water Fish Tank
The Deep-Water Fish Tank offers an immersive experience, making you feel as though you’ve stepped right into the natural environment of the Fuji Five Lakes.
The tank faithfully recreates the unique lava belt terrain found around the lakes, providing an authentic backdrop where various species swim freely. You’ll find popular game fish such as Himemasu (landlocked sockeye salmon) and largemouth bass, both favorites among anglers.
This exhibit isn’t just a highlight for fishing enthusiasts—it’s also a must-see for anyone curious about the ecosystems and freshwater fish of the Fuji Five Lakes.
River Fish Tank
The River Fish Tank is a large-scale exhibit that recreates the natural environment of a river, from its headwaters to its midstream sections.
Here, you can observe iconic Japanese freshwater species in a realistic setting—for example, Yamame and Amago trout, which thrive in the upper reaches, as well as minnows (Oikawa) and catfish (Namazu) commonly found in midstream areas.
By showcasing how fish adapt to different currents and terrains, the exhibit provides a fun yet educational experience for both children and adults.
This is a must-see for anyone interested in learning more about freshwater fish and river ecosystems in Yamanashi.
Special Exhibition Tank
One of the most popular highlights at the Yamanashi Prefectural Fuji Spring Pond Aquarium, “Mori no Naka no Suizokukan”, is the Special Exhibition Tank, which changes its theme every season.
Depending on when you visit, you’ll encounter unique displays. For example, during one photography session, the theme was a Reptile Exhibition, featuring creatures like frilled lizards and Japanese rat snakes (Aodaishō)—rare yet surprisingly charming animals you could see up close.
Past events have included the “Hunter Exhibition”, introducing predatory species such as carnivorous fish and birds of prey. Throughout the year, these rotating exhibits keep visitors coming back for something new and exciting.
If you’re looking for an aquarium in Yamanashi that offers seasonal, limited-time exhibits, this is the perfect spot to add to your itinerary.
Theater Hall
The Theater Hall is a popular area where visitors can enjoy an impressive three-screen panoramic experience.
The short films are designed to be entertaining for both children and adults. Programs include titles such as:
- “The Adventure of Ayu”
- “Freshwater Fish of Yamanashi”
These engaging shows make it easy to learn about the freshwater species and river ecosystems of Yamanashi through dynamic visuals.
Each program runs for about 15 minutes, making it compact and convenient to enjoy in between sightseeing. It’s also a perfect indoor activity on rainy days or a family-friendly stop during your trip.
Special Exhibition Corner
One of the most popular features of the Yamanashi Prefectural Fuji Spring-fed Water Aquarium, “Mori no Naka no Suizokukan”, is its Special Exhibition Corner, where the themes change periodically throughout the year.
During our visit, a quirky exhibition called “The Naming Sense Exhibit” was on display. One of the most memorable highlights was a fish called Ojisan (literally “middle-aged man”). The name comes from the fish’s distinctive whisker-like barbels, which amusingly resemble the mustache of a middle-aged man.
Exhibitions like this put a spotlight on the fascinating names and features of fish, while others focus on their behavior and ecology. Thanks to its rotating lineup of creative displays, there’s always something new to discover at the aquarium throughout the year.
Micro Aquarium Corner
The Micro Aquarium Corner offers a close-up look at tiny freshwater creatures that are rarely seen with the naked eye. Here, you can observe fascinating species such as the freshwater jellyfish (Craspedacusta sowerbii), as well as giant water fleas and other plankton.
Behind the display tanks, microscopes project enlarged images of these organisms onto monitors, allowing visitors to experience the hidden world of microscopic life in stunning detail.
The “Delicious Aquarium”
One of the highlights of the Yamanashi Prefectural Fuji Spring Pond Aquarium, known as “Mori no Naka no Suizokukan”, is the “Delicious Aquarium”—an exhibition area where visitors can learn about the region’s traditional and modern aquaculture.
Here, you’ll discover the history of Yamanashi’s freshwater fisheries and the fascinating biology of farmed rainbow trout. Life-sized models allow you to see and feel the actual size and shape of these fish up close.
Yamanashi ranks third in Japan for rainbow trout production, and the exhibit also introduces the prefecture’s very own hybrid species, “Fuji-no-suke”, a cross between a king salmon and a rainbow trout.
This area is especially recommended for families and children interested in learning about local aquaculture, unique fish species, and regional food culture.
Underwater Camera Corner
The Underwater Camera Corner is an interactive exhibit where you can operate a camera installed inside the tank—making you feel like a real diver exploring the underwater world.
Using the control lever, you can move the camera freely to observe the fish up close, capturing details of their behavior and expressions that are normally hard to see. Uniquely, you can even experience the view from inside the tank looking out, giving you a true fish’s-eye perspective of the aquarium.
This hands-on exhibit is especially popular with families and aquarium enthusiasts, offering a fun and educational way to connect with aquatic life.
Facility Information・Access・Admission
Facility Information
| Address | 3098-1 Shibokusa, Oshino Village, Minamitsuru District, Yamanashi 401-0511 (inside Sakana Park) |
|---|---|
| Phone | 0555-20-5135 |
| Business hours | July–September: 9:00–18:00 October–June: 9:00–17:00 |
| Closed | Tuesdays (the following day if Tuesday is a national holiday), and December 28–January 1 |
| Website | http://www.morinonakano-suizokukan.com/index.html |
Access
