A new study has found that about 90% of marine aquarium fish sold in the US come from wild populations.
Researchers analysed 734 species sold by major online retailers and found only 3% were fully farmed.
Many of the fish are caught from reefs in the western Pacific and Indian oceans, often with little supply chain transparency.
“This trade is incredibly opaque – from reef to retail,” said Dr Bing Lin from the University of Sydney, who led the study.
The research also found 45 species listed as threatened, including Banggai cardinalfish and clarion angelfish, being sold online.
Experts warn that poorly managed wild capture can deplete populations and disrupt reef ecosystems.
Dr Lin called for stronger traceability, eco-certification, and consumer awareness to ensure sustainable sourcing.
“People should know where their aquarium fish come from and whether they were caught responsibly,” he said.