We just returned from Seagrove and were in the gulf, literally each day 9/12 - 9/17. Having never experienced red tide, I didn't notice anything. The fish were very much alive and kept after our feet and legs so much I had to get out of the water.
That said when we left on 9/18 my husband was not feeling well at all (it was crazy hot and humid all week and the beds in our house were hard as rocks so we didn't sleep well - we figured it was that combination) and he has developed a nasty, wet cough. He ran a low-grade fever for about a day if that. Now he feels okay but the bad cough lingers. We heard about red tide in the area on our last day (after we had already been in the gulf that morning of course) and he jokingly said he's got the red tide. I didn't think so but maybe he is right?