A new species of a giant air-breathing fish known as arapaima has been discovered by scientists from SUNY College of Environmental Science and Forestry in Syracuse, N.Y.
Credit: George Chernilevsky

Scientists have found a new species of giant, air-breathing fish in Brazil's Amazon River — the first discovery of its kind in more than 150 years.

The silver fish is a member of the arapaima family, an air-breathing freshwater fish native to the rivers of the Amazon Rainforest that can grow up to 10 feet long.

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It is the first new arapaima species to be discovered since 1847, according to National Geographic.

The discovery was reported in the journal Copeia.

The newly-discovered A. leptosome has a slender body, distinct sensory cavities on the head, a sheath that covers part of the dorsal fin and a unique color pattern.

Four species of arapaima were recognized by scientists in the 1800s, but were lumped into one by British scientist Albert Günther in 1848 — a prevailing wisdom that had largely gone unchallenged until recently.

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Dr. Donald Stewart of the SUNY College of Environmental Science and Forestry in Syracuse, N.Y., has shown that there are actually five species of the giant fish, and made the most recent discovery.

"Until this year, no taxonomist has questioned Günther's opinion about these iconic fishes," he wrote in his findings.

Identifying and understanding all of the arapaima's different features will aid in the health of the fish, the conservation of river ecology and the balance of nature, according to Stewart.

"There is a growing aquaculture industry for arapaima, so they are being moved about and stocked in ponds for rearing," he said. "Eventually, pond-reared fishes escape and, once freed, the ecological effects are irreversible. A species that is endangered in its native habitat may become an invasive species in another habitat.

"The bottom line is that we shouldn't be moving these large, predatory fishes around until the species and their natural distributions are better known. Given the uncertainties, precaution is needed." 

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