A panel of scientists recommended the method last month to eradicate the alien Chinese fish, which grow to more than 3 feet long, feed voraciously on other fish and can crawl short distances on land.
"I feel confident that this is the most effective and efficient course," state Department of Natural Resources Secretary J. Charles Fox said Tuesday in a statement.
More than 100 northern snakeheads were discovered reproducing in the nine-acre Crofton pond earlier this summer, two years after a man dumped a pair of adult fish there.
The department said herbicides will be used to kill vegetation and reduce oxygen for the fish, then a fish poison called Rotenone will be applied. Rotenone is commonly used to control fish populations because it degrades within days and poses no threat to humans or other animals, the department said.
The agency did not say when the poisoning would begin.
Ruled out as options for killing the fish were such things as netting, electrofishing, explosives, the introduction of predators, and draining the pond. All were deemed unlikely to be fully successful.