summer days! It’s too hot to go out, and yet you want spend time staying cool without spending too much money. There’s a place that fulfills these wishes right next to the Kumamoto City Zoological and Botanical Gardens. It’s also a great educational outing for children.

No Tickets Needed! Free Admission!

Next to the west gate of the Kumamoto City Zoological and Botanical Gardens in Higashi Ward, Kumamoto City, the “Waterside Information Center” was established two years ago.

Just by looking at it, it’s an impressive facility. As you walk through the automatic doors, you see a sign. It’s refreshingly cool inside!

The Fish of Lake Ezu

Once inside, you’ll find large panels and fish tanks lined up in a row.

So, what kind of creatures live here?

Japanese eels in Ezu Lake!? It says they are an endangered species according to the Ministry of the Environment!

Apart from the eel, there are ayu sweetfish, and even Japanese sea bass.

Much of Lake Ezu’s water actually comes from natural groundwater springs which filter up through the ground at a constant temperature year-round, which has an stabilizing effect on the lake’s temperature, providing a comfortable habitat for many species of fish. Seabass that swim upstream from the sea end up settling here because of these ideal conditions.

The highlight here are the bitterlings or tanago in Japanese, which are small freshwater fish that inhibit slow-following or still waters and are from the same family as carps and minnows.

Though there are many types of bitterlings, several rare ones are on display here.

The fish in this photo are all bitterlings.

 It’s quite rare to see seven different types of bitterlings in one place!

 There is a type of bitterling called seboshi tabira in Japanese, which has a beautiful pattern resembling stars on its dorsal fin

Here are some slightly flattened, petal-shaped Japanese rosy bitterlings, named for their resemblance to flower petals.

Interestingly, due to interbreeding with invasive species, being able to specifically identify a specifically “Japanese” rosy bitterling is quite rare!

It’s really interesting to see the richness of nature at Ezu Lake, but it also raises awareness about the diminishing presence of native species and the concerns surrounding that. There’s so much to learn from it all.

Summer is the Season of Love for Tanago Fish

These bitterlings enter their mating season in the summer.

During the breeding season, male bitterlings slightly redden their body color to attract females and display dominance to other males.

It’s much like birds, where typically males display more vivid colors.

This color change is noticeable until about autumn, and today I could clearly see the differences between males and females.

I had always thought of river fish as being rather plain, but they are actually quite beautiful.

And contrary to their beauty, in the large tank, a fierce battle among the brightly colored males was also a sight to behold.

Black Bass Swimming in the Fish Tank!!

The panel also does a good job of explaining the negative impacts of invasive species on Lake Ezu’s ecosystem.

The black bass, with its large mouth, is a fearsome predator as it can swallow smaller fish whole, posing a serious threat to native species.

In this facility, even these invasive species are on display.

This is a largemouth bass.

They’re quite large!

Whenever you try to take a photo, they inevitably turn their face towards you (haha).

Maybe it thinks it’s getting fed, or perhaps it sees the camera as food, but they always end up looking directly at you every time you take a photo!

Indeed, while their large mouths might seem intimidating, in truth, the invasive species themselves aren’t to blame.

It’s the fault of humans who brought them in and let them loose. It really makes you think about the consequences of our actions.

At any rate, here at this facility, you can learn a lot for free, and stay cool from the summer heat!

There’s also space where you can do a bit of research on your own.

Taking pictures of the panels and tanks is allowed, making it an excellent spot for summer research projects.

On weekends and holidays around 11:15 AM, free guided tours of the facility are also offered.

The staff members who love Ezu Lake have very interesting stories to share.

Ezu's Mini Aquarium