Invasive sucker fish crisis threatens Thailand’s waterways

Thailand is currently grappling with a severe invasive sucker fish crisis, exacerbated by human actions that have released non-native fish into waterways without considering the environmental impact.

These invasive species are wreaking havoc on Thailand’s native ecosystems, causing environmental, economic, and health-related damage. This issue is frequently highlighted in various media outlets.

In a recent social media sensation, a fish pond owner from Prachinburi province posted a video of draining water from the pond to catch the fish for sale, only to find it overrun with sucker fish, an invasive species detrimental to the Thai ecosystem. The video sparked widespread sympathy for the pond owner on social media platforms.

Today, May 14, the focus is on understanding the sucker fish, exploring their origins, impact on Thai waterways, and why they are considered a danger to the native aquatic life.

A fish pond owner is distraught after two days of water pumping to catch fish for sale yields only sucker fish.

The sucker fish is scientifically known as Hypostomus plecostomus, originates from South America, and is predominantly found in Brazil. It is related to other species such as the Pleco, common in Thailand. The sucker fish has a unique appearance, with a large head, downward-facing mouth, and thick and robust lips used for attaching to surfaces and grazing. Its body sports distinctive black spots similar to those of a gecko.

Ecosystem danger

Initially imported as ornamental fish, Thais kept sucker fish to control algae and food debris in aquariums. However, as they grow to several kilogrammes, owners often release them into rivers and canals, disregarding the suitability of this foreign species to the local environment, leading to its classification as an alien species that disrupts the native ecosystem.

Highly resilient, the sucker fish can survive in various water conditions, including polluted waters. It is omnivorous, with a prolific breeding capability that allows it to lay eggs in almost any environment, leading to rapid population growth. Its aggressive nature and dietary habits, feeding on the mucus and eggs of other fish, have contributed to the decline and potential extinction of native fish species.

One might wonder why, given their abundance, sucker fish are not consumed or sold as an alternative to native species. While sucker fish can be eaten, they are generally not favoured due to their less palatable taste and peculiar appearance.

The sucker fish poses a significant threat to the ecological system by competing for food and causing the gradual disappearance of native species. Therefore, those who keep sucker fish should not release them into natural waterways, reported Sanook.

Moreover, it is advised not to release any fish species into rivers or canals without studying their habits and impact on the local ecosystem.