‘Thousands’ of catfish swarm Canberra longkang, resident says it’s a natural phenomenon

Canberra residents spot huge wave of catfish moving with the tide in neighbourhood canal

A massive school of catfish was spotted moving through a canal in Canberra, sparking curiosity — and some concern — among residents after a video of the phenomenon went viral.

The footage was shared by 41-year-old financial adviser Regine Tan on the Facebook group Singapore Wildlife Sightings on Wednesday (10 Dec).

Captioning her post, she wrote: “This looks like in thousands or in millions. Are those catfish? Where are they going? Is it native to Singapore? (sic)”

Resident questions whether sighting is harmful to ecosystem

Speaking to MS News, Ms Tan said she recorded the video at around 10am along the Simpang Kiri canal.

“My husband has seen this before in the estate group chat, and he didn’t realise there were so many fish,” she said. “I also wanted to know if this phenomenon is friendly to our environment. Some catfish are not native and can be harmful to the local ecosystem.”

Her post quickly drew discussion in the comments, with one user suggesting that the fish could be Sagor sea catfish, a marine species known to swim upstream into canals and even freshwater areas.

The commenter also pointed to a similar sighting at Sungei Simpang Kanan Park Connector back in September.

Another resident says catfish are native & commonly seen there

Another Canberra resident, Mohamad Salleh Bin Saidali, 43, chimed in on the post, saying the sighting occurred near his home along Canberra Street and that he sees the fish moving up and down the same canal daily.

He told MS News that catfish have been appearing in the Simpang Kiri canal for years.

When he first moved there in 2017, there was “nothing much in the canal”.

“But after about three years, I started seeing them coming in,” he said. “In a sense, it became a nursery. Most of them looked young, but there were adults, too.”

Addressing concerns about invasive species, Mr Salleh explained that the catfish seen are locally known as belukang.

“They’re native. They’ve been around for a very long time,” he said. “Malay people call them belukang because of their long white fin spine and big head.”

When asked if the fish were specifically Sagor sea catfish, he said he was unsure, adding that he only knew them by their local name.

Canal supports both freshwater & saltwater species

Mr Salleh also noted that the canal is connected to both freshwater and seawater sources, which explains the variety of wildlife seen there.

“It’s not only catfish,” he said. “From the freshwater side, there are turtles and cichlids. From the saltwater side, there are catfish, mullets, halfbeaks, and even crabs.”

According to him, the fish tend to appear during tidal changes.

“They only come when the tide is coming in or going out,” he said. “They always swim in one direction together. That’s how they avoid predators.”

He added that he spotted another large group on Thursday (11 Dec) at around 11am.

‘I see them even if I don’t want to’

An aquarium hobbyist, Mr Salleh said his interest in nature makes the sightings especially fascinating, though they are impossible to miss.

“My window faces the canal, so I see them even if I don’t want to,” he quipped.

The size of the schools varies, he added, joking that it likely depends on “the parents’ accomplishment during breeding”.

He believes the fish are following food carried along by freshwater flows.

“I think they’re chasing the small scraps and morsels that the freshwater brings in,” he said.

Also read: Monitor lizard tries to swallow catfish whole at Sungei Buloh, mouth gets pierced bloody by fish’s spines