I spent 5 years in the florida keys spearfishing around sharks. When I'd mention to someone where I was spearfishing they would say-ohh that place is too sharkey. Well the reason the sharks are there is cuz the fish are there. Anyways the best grouper i ever had was one that got half eaten by a shark, it bleeds them out to where the meat is super white, almost as white as a new white tee shirt, Im not sure if it can fix up a red fish like that but its sure to improve on a red.