In the arid Southwest, the backyard pool was the equivalent of the white picket fence: a sign the homeowners had achieved middle-class status. But as the foreclosure crisis emptied neighborhoods, the once-gleaming pools -- caked with algae and infested with mosquitoes -- became fetid reminders of all that was lost.

One afternoon in Las Vegas, Robert Cole approached a 3,215-square-foot house on Bracken Cliff Court, armed with his chief weapon against the mosquito scourge: a container of silvery fish. A “For Sale” sign advertised the pool and spa out back. You could smell them from the frontyard.

The deck area near the small pool was decorated with red rocks and outfitted with a blue basketball hoop. On the water’s surface, a slick of green algae inched toward a rubber duck.

Cole tossed four fish into the spa and six into the pool, and a few drops of water splashed him. “Ugh,” he grimaced. “I got that nasty stuff on me.”


Cole, 36, is an environmental health specialist with the Southern Nevada Health District. He and six others are charged with stopping the pools from becoming disease incubators. In recent years, as Sin City turned into Foreclosure City, the team has been swamped.

The number of “green pool” complaints jumped to 2,800 in 2008, from about 1,600 in 2007. This year, the health district received nearly 500 complaints from January through March, an 80% increase over the same time last year.

And there are few signs of complaints trailing off: In the first quarter of 2009, Nevada had the nation’s top foreclosure rate, according to RealtyTrac.

The pool problem exists throughout the West.


“As the economy went south, the number of green pools went north,” said Chris Conlan, supervising vector ecologist in San Diego County’s Department of Environmental Health, which stages weekly helicopter flyovers to spot rancid pools.

California, Arizona and Florida also rely on Gambusia affinis, or mosquitofish. The inches-long creatures can survive for months in stagnant water, and to them a batch of larvae is a prime-rib buffet.

In Contra Costa County in Northern California, officials breed up to 2 million fish a year, and residents bring them home in coffee cans. The county’s Mosquito and Vector Control District has also subscribed to foreclosure listing services to spot possible problems.

“In the past, you’d just tell homeowners to take care of their backyards,” said Craig Downs, the district’s general manger. “But in the last two years, nobody’s been home.”


In Maricopa County, Ariz., which includes Phoenix, authorities are on track to respond to 14,000 pool complaints this year, said John Townsend, vector control division manager. They’ll need a sea’s worth of fish.

“You get backyard swamps here, and it’s no different than in Texas or Louisiana,” he said.

About 50 fish are needed to rid a 400-square-foot pool of mosquitoes, Townsend said, though some neighbors misguidedly douse the pool water with chlorine, wiping out the fish and forcing health officials to start over. Last summer, officials imported fish and bred them in a stingray tank at the Phoenix Zoo. (The rays are relocated to less-sweltering Chicago each summer, Townsend said.)

Desert heat creates other problems. Mosquitoes there breed year-round, and the hotter it gets, the busier it gets for vector control.


The problem has grown so expensive in Nevada that state lawmakers are considering allowing some health districts to put liens on properties whose owners won’t reimburse them for mosquito abatement, said Assemblyman Joe Hardy, one of the bill’s sponsors.

In Las Vegas, Cole began a recent day outside town at a wash where a colony of mosquitofish -- how it got there is unclear -- is thriving. Wearing a Dickies button-down and calf-high waders, he scooped dozens of fish from the mossy water, transferred them into buckets and carted them in a truck to health district headquarters.

Outside a parking lot trailer, he dumped the fish into one of four black 100-gallon horse troughs, each of which hold about 2,000 fish. Then Cole swung by his office -- a bumper sticker on his cubicle proclaims, “Mosquitoes Suck” -- and picked up a list of addresses for his afternoon rounds.

With a few dozen fish in a container, he headed to Desert Wind Drive, where azaleas bloom in some yards and bank-owned signs mar others.


The five-bedroom home was peach-colored, its lawn brown, its palm fronds crispy. The house sold for $429,000 almost four years ago, but in 2008 Deutsche Bank took possession.

“One day, the owner walked over and said, ‘Well, got to go, bye,’ ” neighbor Cal Oliver told Cole, who was greeted with smiles and thank-yous. (Pool owners and pit bulls tend to be less welcoming.)

Cole surveyed the pool, where the water was a few inches deep. Mineral oil, he decided, would be his weapon of choice. He spritzed the oil on the murky rainwater, to suffocate mosquito larvae, and returned to his list.

Cole, who moved here from San Diego County a decade ago, had watched from afar as the Vegas housing market mimicked a roller coaster.


Two things persuaded him not to buy a house. He found prices too high, especially in homes big enough for him, his wife, six kids and three Chihuahuas. And yet, a woman bagging his groceries told him she owned two homes. How could she afford them?

“She’s probably got two green pools now,” Cole said.

Cole drove into a neighborhood of decorative fountains and balconies. The streets were named Bermuda Beach and Swan Lake, and he parked on Aqua Spray Avenue.

In 2003, this five-bedroom, three-bathroom, two-fireplace home sold for $323,000. A year ago, Deutsche Bank took over. Before the residents left, Cole said, they shoveled piles of dog waste into the pool. Why? Who knows.


He’s been here half a dozen times since. The large pool was once stocked with mosquitofish. Then it was drained. Lately, it has held rainwater the color of mud. All Cole could do was shake his head, spray mineral oil and post a notice he’s not sure anyone will read:

“Please maintain the property so it does not become a breeding source for mosquitoes.”

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ashley.powers@latimes.com