Fish tale with a happy ending - hopefully

A creature believed to be a rare deep-water fish Mola mola was found swimming in the Tuen Mun River yesterday morning, with some people initially thinking it was a lost shark or a dolphin.

Residents rushed to the river when they spotted the large fish swimming in the shallow water outside Lung Mun Oasis housing estate - with its fin above water.

They suspected it lost its way from the sea and got into the river.

"How come there is a shark in this kind of river?" a resident said.

Police said they received a request for help at 8.10am, adding there was a suspected shark swimming in the river.

Officers said the fish eventually swam to the ocean.

No one was injured in the incident and the case was classified as "animal found."

A fisherman nearby later identified the fish as a Mola mola, or ocean sunfish, one of the heaviest bony fish in the world.

The fisherman said it is a kind of deep-water fish that is rarely seen in Hong Kong. The one found in Tuen Mun was believed to be young as it is about one to two meters long, he said.

Lydia Pang Lee-yan from WWF-Hong Kong also said they believe the fish to be a Mola mola based on its appearance.

"It is more commonly seen in Taiwan and Japan but it is very rare in Hong Kong. We have one or two records of it back in the 1990s."

A mature Mola mola typically weighs between 247 and 1,000 kilograms, with an average length of 1.8 meters and a length of 2.5 meters. But the species can grow up to three meters and 2.5 tonnes.

The bullet-shaped fish is found in temperate and tropical oceans and is often mistaken for a shark when the huge dorsal fins emerge above the water.

Americans have been urged not to call police when seeing the sunfish.

The word "mola" means millstone in Latin, which is used to describe the fish's appearance. The species survives on jellyfish, small squid and algae and is harmless to people.

At the Tuen Mun River, boatmen sailed their vessels next to the fish, hoping to guide it back to the deep sea.

The fish eventually left after swimming for about three hours in the river.

Some web users in Hong Kong sometimes post Mola mola pictures on online forums when there is a stock market crash as the name sounds like "it's all gone" in Cantonese, representing people who lost money. Others say it is "an unlucky symbol" for the fish to show up in Hong Kong.

In the past, sharks and Chinese white dolphins used to be seen at beaches in Tuen Mun.

In June 2020, a shark was spotted at Golden Beach, which led the Leisure and Cultural Services Department to raise a red flag, telling people not to swim there.

A dead 30cm milk shark was found at the beach the next day.

In 2021, a dead 70cm shark was seen by swimmers at Cafeteria New Beach in Tuen Mun, with no signs of decomposition.

Tuen Mun's Lung Kwu Tan is also one of the areas where people often see Chinese white dolphins, a protected species.

carine.chow@singtaonewscorp.com