In Asia, goldfish are also preferred to be eaten or as pets. But in other countries, such as the United States, Britain and Canada, the population is getting higher and it's making its own anxiety.
The reason is, goldfish are considered as pests. The more the population of goldfish in the lake, it is feared that aquatic plants will not develop and have an impact on native species. For example, the native species became starved because of the invasion of goldfish.
"All goldfish are basically invasive species all over the world. Across North America, Australia, parts of Europe, they're really widespread," said Przemek Bajer, an academic at the University of Minnesota, as quoted by CNN. Here are some stories of anxiety because of goldfish:
\
Not long ago, in Burnsville, Minnesota, a giant goldfish was discovered in Lake Keller. Authority fish is called a giant because unlike when kept in an aquarium or the like, this goldfish can grow up to 38 centimeters.
Whereas goldfish kept in home aquariums usually grow only up to about 5.1 cm. It is suspected that the goldfish was disposed of carelessly by the residents who initially kept it.
Giant goldfish. Photo: Twitter
The local city government has warned residents not to do so as goldfish can contribute to water quality degradation by ruffling sediments and uprooting plants.
"Please don't release pet goldfish into ponds or lakes. They grow bigger than you think and contribute to poor water quality," they wrote on Twitter, complete with a photo of the jumbo-sized goldfish.
In the City of Ontario, it was observed that there are many ponds filled with thousands of goldfish which are considered dangerous pests because they prey on local species and destroy their habitat. In Great Lakes, goldfish numbers have surged since 2015, according to ecologist Jennifer Bowman of the Royal Botanical Gardens.
"It's only getting worse now. These goldfish are very successful if they are together. A few goldfish in a pond could be in the thousands in the next year," he said, as quoted by us from the CBC.
To deal with it safely, currently being formulated several ways. Solutions include lowering the water depth level or using certain chemicals.
However, the use of chemicals can kill all species in the waters, not just goldfish. If such a step is taken, it is necessary to add more native species in the targeted waters.
New research in the UK shows goldfish consume more food than fish of the same type in British waters. This fish eats more than other invasive fish, and is also more aggressive at taking on other competing species.
According to Dr James Dickey of Queen's University Belfast, lead author of the study, that means goldfish pose a threefold threat.
"While the northern European climate is often a barrier to non-native species surviving in the wild, goldfish are known to be tolerant of such conditions and can pose a real threat to native biodiversity in rivers and lakes, consuming resources that depend on other species. ," he said as quoted from The Guardian, Thursday (26/5/2022).
This study does not reveal whether the emergence of more goldfish in the wild is due to many pet owners buying goldfish during the pandemic lockdown and then releasing them into rivers.