Scientists: Fish Are Sick Where BP's Oil Spill Hit Two years after the massive Gulf of Mexico oil spill, scientists say they're finding trouble with sick fish that dwell along offshore reefs and in the deep waters - especially in places where the oil spill hit the hardest. The scientists are unsure what's causing a small percentage of the fish they're catching to have large open sores and strange black streaks. The biggest question is whether contaminants from the BP spill are causing the problems. For now scientists can't say for sure if the spill is the cause or if it's normal to find this number of sick fish. The fish illnesses don't pose an increased health threat to humans, scientists say, but they could be devastating to prized species and the people who make their living catching them.