Neighbors near Lovers Key Beach say the dead fish began appearing four days ago. A red tide advisory was issued Monday.

Fish kills can start when levels reach 10,000 cells per liter. In 20 Florida locations, concentrations were higher than 100,000. Health alerts for red tide have been issued in Lee, Collier counties.

As red tide counts fall in Southwest Florida, Florida Fish and Wildlife suspects the toxic ... for most of Lee and Collier counties with very low concentrations (1,000 to 10,000 cells per liter ...