90.7 WMFE and 89.5 WMFV are Central Florida's primary provider of NPR programming and Classical Music. Part of the community since 1965, providing quality national and local news and programming. We inspire and empower all Central Floridians to discover, grow and engage within and beyond their world.
Support for 90.7 WMFE is provided by

Fighting Zika In Florida Involves Unleashing ‘Mosquito Fish’

Play Audio

A 'mosquito fish'/Photo: Wiki Commons

The hot, wet summer weather Florida is known for provides mosquitoes with perfect conditions for breeding. New cases of the Zika virus are already being reported to county health departments across the state.  Now one Florida county is fighting the pesky insects – with fish.

On a hot, sunny Saturday morning at the Upper Tampa Bay Regional Public Library, Kathy and Dani Dahlberg walk up to a Hillsborough Country Mosquito Control truck holding portable fish tanks – which emit a loud hum.

The new homeowners describe the size of their pond to Mosquito Control officials as about an acre in size on about four acres of land.

County officials are giving away “mosquito fish” – a guppy-like, native freshwater fish for free to residents.

Like they do leading up to every hurricane season, mosquito control officials across the state have amped up their efforts to fight mosquitoes that might carry the Zika virus. This includes spraying Naled, a pesticide widely used to fight Zika-carrying mosquitoes in Florida and across the nation.

Use of the pesticide riled up controversy in Miami Beach last year when protesters interrupted a city council meeting to challenge its use. The city council then urged Miami-Dade County to pursue other alternatives. More recently, a University of Michigan study shows a possible link between Naled and motor function issues in babies.

While mosquito control officials say the spray is safe in small amounts, they also say it’s more efficient to focus on preventing mosquitos from laying and hatching eggs, than to fight the bugs in their flying form.

Ron Montgomery is with Hillsborough County Mosquito Control. Prevention is key, but it’s not always easy, he said.

“The rainfall and the heat are directly related to mosquito production,” said Montgomery. “The hotter it is and the more nutritional substance that is in the habitat for the mosquito to eat, the faster they develop.”

That’s where “mosquito fish” come in.

“They go from an egg to an adult mosquito sometimes in three or four days,” he said, “which makes that challenge to treat that larval habitat even that much more difficult.”

When Kathy Dahlberg and her husband bought their property in Odessa earlier this year, Southwest Florida Water Management District, known as “Swift Mud,” told them mosquito control was top priority:

“After we bought the house, we did all the kind of research you do about how you take care of it, and we called swift mud, right, to say, “what else do we need to do’,” Dahlberg said.  “And this was among the first things, to make sure we take care of mosquitos.”

The women walk away with state fair-style plastic baggie of mosquito fish. Most of them have swollen, translucent bellies and will soon give birth to live babies.

So far this year, more than 70 people in Florida have tested positive for Zika. Most of the cases are travel-related, and most people who contract it don’t show symptoms.

But pregnant women, including almost 50 diagnosed with Zika in Florida this year, are at serious risk because the virus has been linked to microcephaly in babies.

Vilma Vega is an infectious diseases specialist in Sarasota. She’s just as concerned about other diseases, like a recent outbreak of yellow fever in Brazil.

“It’s not going to take much for such a disease to get transferred into any other country,” said Vega. “We definitely need to keep our eyes open.”

Hillsborough County Mosquito Control Office’s Ron Montgomery said Floridians who don’t live in his county can still easily get the mosquito larva known as munching fish.

“If you’re not part of a mosquito control program that has them, which I would encourage you to check first, you can get them at pet stores,” said Montgomery. “You can buy them mail order and have them shipped to you overnight.”

There are other measures residents can take to keep mosquito populations down and prevent the spread of Zika: empty containers of standing water, recycle old tires, cover exposed skin with clothing, and use bug spray.

WUSF is a partner with Health News Florida, a statewide collaborative reporting on health care.

Health reporting on WMFE is supported in part by AdventHealth.

Get The 90.7 WMFE Newsletter

Your trusted news source for the latest Central Florida news, updates on special programs and more.

Stay tuned in to our local news coverage: Listen to 90.7 WMFE on your FM or HD radio, the WMFE mobile app or your smart speaker — say “Alexa, play NPR” and you’ll be connected.

WMFE Journalistic Ethics Code | Public Media Code of Integrity