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Escapee Fish Thrives Across Western US
16 Aug
Summary
- Asian pond loach escaped a California farm in the 1930s.
- Fish survived harsh conditions, breathing air and burying in silt.
- Established populations appeared in four western states by 1991.
An Asian freshwater fish, the pond loach, escaped a California goldfish farm decades ago and has since established populations in waterways across western states. Initially introduced to the U.S. via the aquarium trade, these fish are now found far beyond their original point of escape. Historical records indicate their presence in California as early as 1963.
The pond loach possesses extraordinary adaptations for survival. It can tolerate low oxygen levels, warm stagnant water, and even periods of drought by burying itself in silt and breathing air. These traits allow it to persist in marshes, ponds, and drainage channels, making them difficult to contain once released into suitable habitats.
This resilience has facilitated a broader invasion. The species was documented in Washington by 1978, Idaho by 1985, and Oregon by 1991. Human activities, including aquarium releases and transport from fish farms, are considered significant pathways for its spread beyond its native Asian range.
