Researcher Emma DeRoy tells 4 In Your Corner part of the problem is that lionfish can live in every part of the Gulf.
"They're habitat generalists," says DeRoy whose work at Vester Field Station focuses on lionfish. "They'll thrive in sea grass, mangroves, corals - anything with structure," she adds.
DeRoy says lionfish also tend to eat the small fish that eat algae off coral. If those small fish aren't around, there's nothing protecting living coral from all that algae.
"Then the algae overgrows the coral and basically suffocates it," she says. "And then you get coral dying off."
She says lionfish also grow up faster than local species like grouper - giving them a head start on establishing themselves in a habitat and eating whatever they want.
"[Lionfish] mature within a year, where lot of grouper take around 4 to 5 years," says DeRoy.
"I think the other big factor is they re-produce so often and they produce so many eggs," says Parsons.
"Their population can just explode." he adds.
Parsons estimates their reproductive rate to be astronomical.
"Somewhere on the order of 2 million eggs per female every time they spawn," says Parsons. "And they may spawn multiple times per year."
"That's a lot of youngin's," he adds.
Charter boat captain Billy D'Antuono tells 4 In Your Corner huge numbers of lionfish are being hauled in from the northern Gulf off the panhandle of Florida.
"They'll go and clean off a spot and get 500, and they'll go back the next week and there's 500 more," says D'Antuono.
"They're bringing back thousands of them in a day," he adds.
Some say the biggest hope for getting the lionfish population under control is human consumption.
"The one good thing is they are a delicious fish," says Parsons.
"Lion fish are just very good to eat," says D'Antuono. "You can eat it as sushi," he adds.
D'Antuono is quick to point out lionfish are not poisonous - just venomous. He says that distinction matters.
"The venom is only in the spine, so the meat is very good," he says. "It's one my favorite fish to eat."
More Florida restaurants are now selling lionfish, and more stores (Whole Foods for example) are selling it at prices that create financial incentive for the commercial fishing industry.
"It's the same level as grouper prices, $24 a pound," says D'Antuono.
D'Antuono is hoping to generate more interest in hunting lionfish by posting videos of his spearfishing adventures on his website.
As researchers look for ways to get the lionfish population under control, they're calling on you to do your part.
When 4 In Your Corner asks Dr. Parsons what you should do if you see a lionfish, he response is simple but direct. "Kill it," he says. "And then eat it. Remove it from the environment."
D'Antuono recommends you kill lionfish carefully, though, as their spines are venomous.
He's been stung before and described the pain as memorable. "It's like someone putting a nail in your hand and somebody slamming the nail in your hand for about two hours," he says. "It's very painful."
But he fears the bigger pain lionfish will inflict will be on the fragile ecosystem in our Gulf.
"They've invasive," he says of the fish that threaten to crowd out native species. "Over the years, these fish could be the only thing left."
D'Antuono is encouraging others to join him in spearfishing lionfish. He even organizes tournaments - telling Fox 4 he's hoping the next one will be this summer at Three 60 Market in Naples.