Using a flashlight under the cover of darkness, he placed a ladder into the sewers and another city was revealed. He tied the light to a step and tried not to make too much noise. The water was up to his ankles. He could not see beyond 10 feet, but that was enough. He started to throw food around and after a while the animals arrived. That’s what he was there for: to hunt clarias living under the Dorticós Avenue in Cienfuegos.

Mr. F. was getting good fishing, but after police caught him, the practice stopped on that avenue for a while. Until others started doing the same thing.

“They went down the sewage to install a draining,” the neighbors say. “That’s when they saw them.”

A video posted on social media shows a white coat that functions as a sign to the cars that they should deviate from the path marked.

The video shows a small group of people watching the hunting party in broad daylight. The man below the street hits the clarias on the head with a machete, another man over the street hitches them up to the surface with a wire and places them on the curb. These are large creatures.

“That day alone they filled five bags,” the witnesses said. “And they came two weekends in a row.”

No one knows the exact site where this species arrived to the sewers of Cienfuegos. Some people suspect that during a flood they entered through a gap that ends below the streets.

Specialists from the Cuban Ministry of Science, Technology and Environment (CITMA by its Spanish acronym) claim that this fish now slithering through the sewers is an invasive alien species that destroys all wildlife.

Breeding the claria in Cienfuegos and in many other places in Cuba has been marked by lack of control of biological security measures, experts assert. That’s why this fish has spread across the island.

The fact that they are highly adaptable, resilient and free-living animals has allowed the clarias to settle in any ecosystem and even jeopardize some. In the Cienaga de Zapata peninsula, this type of catfish was damaging many prehistoric and endemic species like the manjuarí, according to a report by Cuban newspaper Juventud Rebelde in 2006.

CITMA delegates work in several provinces to control invasive alien species. But in the specific case of Cienfuegos, they only manage the wild dogs in the fields of Guamuhaya and the green mussel of the Bay of Jagua.

Also, the construction under Dorticós street originally was a storm drain. But many people who built new homes in the area connected their bathrooms pipes or disposed waste from pig pens there, turning the storm drain into a sewage. That’s how a new ecosystem with abundant food for the clarias emerged there.

CITMA researchers warn about the risks of consuming meat from a claria that has been captured in sewers, among so much filth and dirt. However, witnesses of the “urban fishery” said that several specimens were sold that same day.

Technicians from the Water and Sewage Company told the local press that they don’t have cameras able to visualize what happens inside the sewage networks.

Although nobody can estimate the number of clarias that now live in the sewers of Cienfuegos, they are said to be numerous. The image of people pulling these animals from the sewage system in broad daylight paints a clear picture of the situation.