There's something primal that leads people to wonder what's lurking below the surface of any large river. Humans seem to be hardwired to be both fascinated by, and somewhat fearful of, Volkswagen-sized catfish. Soon a remarkable collection of freshwater fish that can reach such legendary sizes will be on display at the Tennessee Aquarium. The new River Giants exhibit, opening April 28th, features amazing species that grow to enormous proportions in the wild. “These guys are the Goliaths of freshwater,” said Thom Demas, the Aquarium’s curator of fishes. “And, for the first time anywhere, people will have an opportunity to see a global collection of these giants in a single display."

Giant pangassius catfish, that can reach lengths of more than nine feet in the wild, will be joined by a seven foot beluga sturgeon, impressive Australian whiprays, beefy barramundi and a menagerie of other freshwater creatures from around the world. Demas says some species like marbled eels, ghostly-white alligator gar and wallago will add a bit of the weird to this collection of monster fish. “The wallago catfish is one of my personal favorites,” said Demas. “It has the face of a bullhead and an eel-like body. In Southeast Asia, wallago can grow to eight feet in length.”

Redtail catfish, feisty fish with unique markings and very long whiskers, will be another crowd favorite. They'll be found prowling near the bottom of the exhibit while prehistoric-looking arapaima slowly patrol the waters above. Demas predicts guests will snap a lot of pictures of these massive predators. “The arapaima don’t just look powerful, they’re more than 100 pounds of pure, angry muscle.” Demas and other staffers have been in the water working with lots of massive fish while getting the exhibit ready for visitors.

National Geographic Explorer Dr. Zeb Hogan has also had many face-to-face encounters with titanic freshwater fish. Among the 20 species he’s highlighted for his popular National Geographic television series, “Monster Fish,” Hogan’s team documented a 650 pound Mekong catfish and a freshwater stingray with a 12-foot diameter. Hogan will be in Chattanooga for the Aquarium’s 20th Anniversary and grand opening of the River Giants exhibit on April 28th. “It’s pretty easy to love, and to be curious about, these fish,” said Hogan. “They are really hard to find in the wild and most of them occur in very remote parts of the world. The River Giants exhibit is great because, while most of us are not going to have a chance to come face-to-face with a giant catfish or freshwater rays in the wild, we’re afforded that opportunity by going to the Tennessee Aquarium.”

In spite of their ability to reach jaw-dropping sizes in the wild, most of these river giants are facing extinction in our lifetime. Some megafish species have recently disappeared forever. Hogan went searching for the Chinese paddlefish but ended up documenting what others had suspected – that this species is now extinct. “I worked with the scientist who had been searching the Yangtze River for these fish for decades,” said Hogan. “My understanding is the last Chinese paddlefish was seen in early 2007.”

A seven-foot lake sturgeon will be among the river giants in the new display. It represents hope for the other freshwater species on the brink. Today anglers are reporting these ancient-looking fish along virtually the entire length of the Tennessee River. Hogan points to the work of the Tennessee Aquarium Conservation Institute and its partners as a model for other giant fish that are vanishing. He believes that making a connection to these species by watching Monster Fish or seeing some of them first-hand in River Giants is an important step toward helping other big species. “We need to increase awareness to make sure everyone knows what’s happening in the wild,” said Hogan. “Without that knowledge, there’s no support to try and better protect these species.”

Collaborating with National Geographic on this new exhibit extends the freshwater conservation focus that has been the Tennessee Aquarium's hallmark since opening in 1992. The National Geographic Society’s global freshwater initiative aims to inspire and empower individuals to preserve the extraordinary diversity of freshwater.

“We are proud to collaborate with the Tennessee Aquarium and work with our explorer Zeb Hogan to protect life that rivers, lakes and wetlands sustain,” said Alexander Moen, Vice President of Explorer Programs at National Geographic. “The magnificent creatures showcased in this exhibit shine a bright light on the relationship we have with our planet and help tell stories that are trademark of National Geographic.”

 River Giants is yet another example of how visitors can have fun tapping into their fascination with some of the world's most interesting fish. “We have a lot of amazing animals in both Aquarium buildings," said Demas. “And I think this new collection of fish is a great way to celebrate the Aquarium's freshwater roots on the Tennessee River.”Megafish Coming to Tennessee Aquarium