Red tide is caused by an outbreak of micro-organisms in the water which deplete it of oxygen, causing large fish kills and respiratory irritations such as cough, watery eyes, scratchy throat, and sometimes, headache. Unless you have pre-existing respiratory conditions such as asthma, it is usually not dangerous. It is not unsafe to swim during a red time, but sometimes there are bans on harvesting shellfish if the bloom has been of a long duration.
Little Gasparilla Island usually suffers from a red tide 2-3 times a year. Usually it is worse in the late spring and summer, but no one can predict it's approach. It occurs all along the Gulf Coast usually from Tampa to Marco Island.
If the bloom is severe, it is best to keep the house closes and stay indoors. If there is a fish kill, it is best to bury the dead fish in the sand right at the beach to remove the smell and then the beach is usually tolerable.
Red Tide + Dogs
Dogs are much more susceptible to the organism than humans. If they sleep outdoors, swim a lot or eat dead fish on the beach, they can succumb to red tide toxins which can have severe short-term neurological effects, including temporary blindness, stumbling and minor seizures. These effects are usually short-lived. If your dog has been exposed to the toxin and you notice stumbling, contact one of the local vets immediately. Usually the dog will recover within a day or two if properly treated. The dog should NOT be hydrated with saline because the organism thrives in salt water. Most vets want to hydrate as a matter of course, please be sure to tell them not to.