A Vietnamese citizen was arrested at Adelaide Airport on Saturday after one of the world's most expensive aquarium fish was found alive in a bag hanging around his neck.
The man was frisk-searched after stepping off a flight from Malaysia, and the 34-year-old pulled out the bag containing a fully red Asian arowana, news.com.au reports.
In Australia, it is illegal to own an Asian arowana unless it is legally imported.
"The ABF (Australian Border Force) is committed to stopping the trade in rare animals and protecting our delicate natural wildlife from the potentially devastating impact of foreign diseases and predators," ABF regional command South Australia chief Superintendent Brett Liebich told news.com.au.
"The ABF takes the illegal wildlife trade seriously and we will continue to work collaboratively with our partners to detect, disrupt and deter illegal activity at our borders."
Liebich said the fish had to be euthanised, as illegal imports of toxic animals could introduce serious pests and diseases that pose a significant biosecurity risk to Australia.
The maximum penalty for wildlife trade offences under Australian law is 10 years' imprisonment and a fine of up to $210,000 for individuals or up to $1,050,000 for corporations.