Processing Goldfish: From Domestic Animals to Threats in Lakes and Rivers | Why not throw them in the toilet

In recent years, the pez dorado (goldfish), known as Carassius auratus, has become a real problem for local species of swamps, lakes and rivers From all over the world.

In the wild, they can weigh up to 2 kg and exceed the size of a rugby ball. These invasive species have become a real threat to local ecosystems.

Authorities in Minnesota, United States, have warned citizens not to release these fish in lakes and rivers across the state, after finding several giant specimens in Lake Kelle.

The most common way for domestic fish to reach rivers or lakes is through the sewage system. It is difficult to discern whether people who dispose of their animals by rinsing them believe they are “free” or ensuring their death in sewage treatment plants. But in reality neither of the two alternatives is safe, and the first ends up turning the little goldfish into a nightmare for the original natural environment.

Drainage systems collect rainwater and snowmelt, as well as waste from domestic sewage, which usually passes through sewage treatment plants. But when it rains a lot, the “pipes that carry the wastewater are overflowed and, to protect homes, businesses and the treatment plant, wastewater overflows will be discharged into nearby waterways. with little or no treatment, ”the specialists explain.

Alert to “released” fish

In the town of Burnsville, United States, just a few days ago, they alerted the whole community to the dangers of throwing these fish into local lakes. “Please don’t release goldfish into lakes or ponds! They get much bigger than you think and contribute to the deterioration of water quality,” the publication says.

Damage to the ecosystem

Captive breeding, as with any species, causes the animal to change its way of life and therefore adaptation to this also produces physical changes in goldfish. In the wild, these creatures reproduce very easily. Aquariums in homes limit their growth.

The problem lies in their return to nature, because the Carassius They feed on the eggs of other local fish and mosquito larvae in the water (making them natural insecticides). To feed themselves, they use a technique that involves shaking the ground. This implies a second problem: by lifting the mud from the bottom, it floats previously buried nutrients, activating excessive algae growth.

Experts also warn against the consequences of discharging water from aquariums into rivers and lakes. Diseases and parasites that goldfish can carry and pose a threat to local species accumulate in these stagnant waters.

Goldfish, also known as the three-tailed goldfish, is the domestic version of the Chinese river carp (Carassius auratus), a species of freshwater fish. He began to be captive-bred about 2000 years ago, being one of the oldest species of domestic fish and is currently the leader in fresh and cold water aquariums.

A study conducted a few years ago in Australia, in which they tracked 15 goldfish for a year, were able to determine how these species migrate.

“We discovered that these fish can migrate from canals (where they are left by their owners) to the river and from there to the swampy system where they lay their eggs “, pointed out the investigation. This means that in a year they can travel a distance of over 230 kilometers.