The Hillsborough County Health Department on Thursday reported a red tide bloom in the waters of lower and middle Tampa Bay.
Officials say the blooms are located near Moody Point, Manbirtee Key, Camp Key, and Little Cockroach Island.
They say the blooms could cause fish kills in some areas.
Residents may experience respiratory issues that can mirror a cold. Others with breathing problems, such as asthma, could experience more severe symptoms.
Anyone experiencing breathing issues should stay away from beach areas or remain indoors.
The Florida Poison Control Centers have a toll-free number for reporting illnesses at 1-800-222-1222.