Queensland Museum says a new species of rockcod, or grouper has been confirmed after two years of testing DNA.
After commercial fishermen sold the fish to market in 2017, experts determined the species is native to the central part of the Great Barrier Reef.
Fish expert Jeff Johnson said the fish were hard to get a hold of, as they were popular among buyers.
"We've had inquiries from fishermen, from scientists, from the boating and fisheries [department] — every time I'd say 'have you still got the fish' and then they'd say 'oh, we've already ate them or already sold them'," Mr Johnson said.