Australian conservationists are fretting after 20,000 yellowtail kingfish escaped into the ecosystem off Port Stephens, NSW.
Last week, the "ravenous" fish broke free after their fish-farm sea cage was destroyed during a storm.
The joint NSW government and Tasmania-based Huon Aquaculture project has now lost half of its stock, worth NZ$2.2 million. While 3000 kingfish have been recaptured, 17,000 still remain on the loose.
Marine Parks' Association chairman Frank Future says the impact could be devastating for local wildlife.
"The pen that had the release was mangled and now we have thousands of mature kingfish released into the wild, nothing will be safe from them," Mr Future told the Newcastle Herald.
"They are voracious feeders and from what I understand they are ravenous. Once they realise they won't get any food in the form of pellets they'll be eating anything they can find. I don't want to think about the impact on wild species."
But the news has had another impact - on fishers. Eager boaties are flocking to the area to catch their bag limit.
The fish are hungry and used to being fed automatically, and there are reports they're even taking a bare hook.
A spokesman for the NSW Department of Primary Industries told the Newcastle Herald the kingfish weren't considered a "biosecurity risk".
"The farmed yellowtail kingfish are of the same genetic stock as wild populations with broodfish being sourced locally," he said.
"The farmed fish are from local parent stock and are health checked on a routine basis, so they are not considered a biosecurity risk."