underground lakes Archives

Subterranean Fish: Species Found in Underground Lakes

Posted on February 21, 2023February 20, 2023 Camille Smith

When it comes to freshwater aquatic life, there’s so much that’s still unexplored. Surprisingly, most of them won’t be found in the open waters outside your lake house. Many species of fish dwell only in underground lakes, often living in caves that are unreachable by boat. In fact, there are more than 200 distinct species of cavefish, also known as subterranean fish, existing on almost every continent besides Antarctica. However, due to their underground locations, this number only scratches the surface of the abundance of species that likely exist. Today, we’re taking a look at some interesting fish species found in underground lakes!

Alabama Cavefish

One unfortunate issue with fish species in underground lakes is their endangered state. More than 50 species are recognized as threatened by the International Union for the Conservation of Nature (IUCN). Among them is the Alabama Cavefish. These underground-dwelling fish live only in Key Cave which is located in Lauderdale County, Alabama. Their population sits at only 100 fish, making them one of the rarest cave-dwelling species in North America.

Dragon Snakehead

Photo courtesy of Ralf Britz / Naturhistorisches Museum Bern via Smithsonian Magazine

Just last year, a new type of underground fish species was discovered. Living below the Indian state of Kerala, a plethora of intriguing fish exist – many of which are found nowhere else on earth. The recently-discovered dragon snakehead fish was originally seen in 2019 after tragic floods in the state. Thought to be part of the Channidae family, scientists dismissed it as a common cavefish and named it Gollum the character from Lord of the Rings. However, after scientists have examined this fish in further detail over the past few years, it has become evident that the fish belongs to an entirely new family of snakeheads: Aenigmachanna. The realization that the dragon snakehead fish has unique characteristics all their own is one of the most exciting discoveries about aquatic life in the last decade.

Mexican Cavefish

There are two types of Mexican tetra: one is native to the Rio Grande, as well as other parts of Mexico and southern Texas. However, the other type of Mexican tetra (also known as Mexican cavefish or blind cave tetra) can be found in caverns and underground caves throughout the region. As a tough subtropical fish, they enjoy warm climates and feeding along the bottom of the lake. However, one of the most interesting things about the Mexican Cavefish is its evolution. Over time, this species has evolved to blindness. For most species, this transformation would be maladaptive and would only occur in a mutation. However, for the Mexican cavefish, the lack of eyesight is helpful for living in dark waters. Instead of attempting to see their surroundings, they get by using a lateral line system to detect changes in water vibrations.

Hyaline Fish

While many subterranean fish species have existed for hundreds of years, the hyaline fish trumps them all. Documented almost 500 years ago in 1541, the hyaline fish is the oldest recorded species of obligate cavefish. Found only in Yunnan, China, this species is considered threatened. Like many other cave fish, it lacks scales and coloring, as well as external eyes. But the Sinocyclocheilus hyalinus’s most unique characteristic is its skull horn and dorsal hump.

Rattail Knifefishes

Also known as glass knifefish, these fish live in freshwater streams in Panama and South America. However, a specific subspecies of glass knifefish, Eigenmannia vicentespelaea, specifically inhabit caves. This subterranean fish species is the only cave-dwelling member of the knifefish family. Unlike other knifefish, it has a translucent body and small eyes. Specifically, they can be found in caves near Sao Domingos, a city in the Goias state of Brazil. It’s endemic to this single cave system, meaning that these fish don’t exist anywhere else in the world.

These underground fish species — plus thousands more like them — are all part of the freshwater systems we don’t see. Next time you’re on the lake, remember that there’s more to aquatic life than meets the eye!

The World’s Smallest and Largest Underground Lakes

Posted on November 27, 2021January 8, 2022 Camille Smith

Photo courtesy of John Karakatsanis Travelgrove

Did you know that 71% of the earth’s surface is made up of water? Mostly referring to the oceanic waters of the world, this statistic reminds us how integral that water is to life on earth. However, not all water is surface-based. In fact, there are multiple bodies of water that exist beneath the surface of the earth. From subglacial lakes to cave lakes, hundreds of intriguing bodies of water lie tucked away in the most unexpected spots on earth. Today, in honor of all the lakes we can’t see, we’re covering the smallest and largest underground lakes!

The Largest Subglacial Lake

Given the expansiveness of Antarctic lakes, it’s no surprise that the largest underground lake in the world is subglacial. As opposed to typical underground lakes, a subglacial lake simply refers to one that is covered by a layer of ice. In the case of Lake Vostok, this layer happens to be 2.5 miles. Because of this lake’s hidden nature, its existence was unknown until the 1990s when a Russian pilot and geographer noticed a unique oblong shape from the air.

Today, the lake is part of Vostok Station, a Russian research hub in central Antarctica. Although scientists disagree about whether the lake existed before or after the East Antarctic Ice Sheet was formed, they do agree on one thing — the lake’s ecosystem is fascinating. With a temperature of -89 degrees Fahrenheit, the presence of life in earth’s coldest temperatures has implications for the possibility of life on other planets.

The Largest Non-Subglacial Underground Lake

The country of Namibia is famous for a lot of natural wonders — the treacherous skeleton coast, the world’s highest sand dunes, and most of the endangered black rhino population. Beyond these wonders, the country is also home to the largest non-subglacial underground lake. Located in the Otjozondjupa Region in Namibia, Dragon’s Breath Cave was discovered in 1986 and named for the moist air that can be seen from the cave’s entrance, resembling dragon’s breath. At least 16 invertebrate species live in these zero-sunlight conditions, as well as a few other species such as golden catfish, the most isolated fish in the world.

The Smallest Underground Lake

In a small island in the southwest Pacific, the Moqua Well sits on the island of Nauru. In this tropical location, a limestone plateau formed low cliffs, which later produced caves. Inside, Moqua Well is a 16 foot deep freshwater lake. During World War II, this lake was a primary source of freshwater for the people living on Nauru island. Its integral nature during the war earned its name “well” instead of “lake.” After the war, it was primarily a destination for partiers to drink. However, after an inebriated man fatally fell into the well, the lake is now closed access.

The Smallest and Clearest Underground Lake

Although it is larger than Moqua Well, Melissani Lake is another one of the world’s smallest underground lakes. It also happens to be a fascinating tourist attraction. Close to the mainland of Greece, it’s located in Melissani Cave on the Greek island of Kefalonia. According to Greek mythology, Melissani was the cave of the nymphs, female deities who are usually personifications of nature. Tourists have remarked on the clarity of the water, which can make boats look as though they’re floating on air. While its length is only 3 miles long, it’s beauty is breathtaking and certainly worth a visit for any travelers to Eastern Europe.

We hope you’ve enjoyed learning about some of these underground lakes across the world!

Underground Lakes Across the World

Posted on October 4, 2021October 22, 2021 Camille Smith

Photo courtesy of Hoang Trung/Shutterstock via Fodor’s Travel

As lake homeowners, we may have one idea in our heads of what a lake looks like. A visible body of water, surrounded by greenery or mountains, with an abundance of wildlife and fish. However, for some lakes, there’s more than what meets the eye. In fact, there are plenty of underground lakes across the globe. Although they’re hidden, these lakes are stunning, full of natural history, and frankly, are great travel destinations. Check out some of the most fascinating underground lakes across the world!

Lake Vostok

Location: Antarctica

Lake Vostok, a subglacial lake at the heart of Antarctica, is probably one of the most enigmatic lakes in the world. Sitting beneath the ice, stretching 3,281 feet deep, this lake has captured the attention of scientists who believe that its frigid climate may have implications for life on other planets. The lake’s existence was first posted by a Russian geographer who noticed its seismic soundings during the Soviet Antarctic Expeditions in the late ‘50’s and early ‘60’s. From there, the Russian research site, Vostok Station was founded. Today, researchers continue to explore this underground lake’s unparalleled features.

Dragon’s Breath Cave

Image courtesy of africanglobe.net via Gondwana Collection

Location: Namibia

Many of the world’s largest underground lakes are subglacial. But not all of them. Dragon’s Breath Cave, found in the Otjozondjupa region of Namibia, is actually the largest non-subglacial lake in the world, thought to be at least 430 feet deep. Divers have not been able to chart its depths further, due to its underground location. Sitting 330 feet below the earth’s surface, it wasn’t discovered until 1986. The group of explorers felt a breeze coming from the cave, and knew they needed to explore. The humid air earned its name — Dragon’s Breath.

Craighead Cavern

Location: U.S.A.

Some underground lakes might be closer to home than we think. In particular, Craighead Caverns is the second-largest underground lake in the world. It’s also the largest underground lake in the U.S.! Also known as the “Lost Sea”, it has been designated as a Registered Natural Landmark by the U.S. Department of Interior. Located between Sweetwater and Madisonville, Tennessee, you can actually take boating adventures through the caverns. Also known as the “Lost Sea” this spot is a wonderful tourist destination for anyone in the southeast.

Lake Martel

Location: Spain

More than 80 feet beneath the surface of Majorca, an island near Spain, lies Lake Martel (in Spanish, Cuevas del Drach). It sits at the bottom of the Caves of Drach, part of a group of four caves that lie beneath this island. Since Lake Martel’s discovery in the 1880’s, the caves have been a popular tourist destination where people from across the world can enjoy guided boat tours. Some tours even end with a live concert! An unconventional, yet thrilling way to enjoy live music on the lake.

Son Doong Cave

Image courtesy of Ryan Deboodt / Oxalis Adventure Tours via Lonely Planet

Location: Vietnam

Translated in English to “mountain river cave,” Son Doong Cave just so happens to be the world’s largest cave. Located at the border of Laos and Vietnam, it is the largest known cave passage, measured by volume. The passage is over 3 miles long and 660 feet high, allowing lush vegetation such as moss to develop along the passage walls. This cave isn’t new either — it developed somewhere between two and five million years ago when limestone was eroded by river water underneath a mountain. Within its walls is also a rushing river which is connected to another cave, Hang Thung.

These fascinating lakes are only a handful of the underground lakes that exist across the world. With travel restrictions lifting soon, don’t hesitate to make these underground lakes next on your travel list!