Lurking beneath the surface of a swamp in Singapore, a creative lived undetected. Decade after decade through survey after survey, the animal eluded researchers. Not anymore.

Tan Zhi Wan and Elysia Toh were surveying the Nee Soon Swamp Forest in central Singapore for decapods, a crustacean group that includes crabs and lobsters, when another “unidentified” animal caught their eye, the Lee Kong Chian Natural History Museum said in a Tuesday, March 14, news release.

The pair of researchers didn’t have a permit to collect the creature, so they photographed it and let it go, museum officials said. Intrigued, they began researching the animal.

Returning to the swamp, the scientists placed traps baited with chicken sausage to lure the creature back, according to a study published March 3 in the Raffles Bulletin of Zoology.

Their efforts were successful. The researchers identified the “elusive and cryptic” animal as a “poorly known” species of catfish: the Encheloclarias kelioides catfish, the study said.

This species of catfish was only known to exist in freshwater peat swamps of Malaysia and Indonesia. The sighting at Nee Soon Swamp Forest was the first time the species had ever been found in SIngapore, researchers wrote.

The Encheloclarias kelioides catfish is a relatively small freshwater fish that lives deep within acidic swamp habitats, the study said. The animal is brown and grows to about 4 inches in length.

Researchers have routinely surveyed freshwater fish in Singapore since 1973, but the catfish went unnoticed, the authors wrote. After finding the fish in three different areas of the swamp, scientists have determined that the species is native to Singapore.

The animal’s preferred dense and hard-to-study habitat “may have helped it to lay low not just in Singapore, but also in Southeast Asia more generally,” museum officials said.

Although more sampling is required to understand the full range of this catfish, researchers recommended the fish be added to the red list of critically endangered species in Singapore, the release said. They also emphasized the “importance of conserving” the swamp forest.

Nee Soon Swamp Forest is part of the Central Catchment Nature Reserve near the center of Singapore, according to the country’s National Parks Board. Singapore is an island country composed of one city-state. It is south of Malaysia and north of Indonesia.

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