Red Tide is officially known as Harmful Algal Blooms, and they periodically occur in oceans. Right now, the west coast of Florida is taking a hit. Dead fish of all sizes washed onto the shore with the tides. The harmful algae in the Gulf of Mexico waters off of Florida is called karenia brevis. It causes oxygen levels in the water to drop greatly, killing marine life. For some people, karenia brevis can cause coughing and sore throats when it’s breathed in.