Biosecurity New Zealand has seized and destroyed 300 genetically modified tropical fish.
Concerned members of the public alerted authorities after seeing the zebra danio fish - popular with ornamental fish enthusiasts - for sale on the internet.
Biosecurity incursion manager David Yard said the operation at four premisesin Christchurch yesterday involved seizing and destroying the fish after genetic testing confirmed they had been genetically modified with a red fluorescent protein to make them a bright red/pink colour.
The Ministry of Agriculture Quarantine Service had unwittingly allowed into the fish into New Zealand under the false impression they had been dyed.
Mr Yard said they posed an "extremely low risk in biosecurity terms" as they were unlikely to enter the food chain or cause any environmental impacts.
"They are tropical, so are unlikely to be able to survive outside a temperature-controlled tank," he said.
"The presence of these fish in New Zealand has not, however, been authorised and they are illegal new organisms in breach of the Hazardous Substances and New Organisms (HSNO) Act."
Biosecurity is now tracing fish that have been sold and wanted anyone who had bright red/pink coloured danios, or knew people who kept them, to contact Biosecurity on the freephone 0800 809966.
Arrangements would be made to collect and destroy the fish.
It was thought the fish were either part of, or bred from, a consignment of red danio that was imported from Singapore this year and cleared by the Quarantine Service.
