Actually, Discovery did a study sometime back and these can carry viruses, acids, pesticides, bugs...A lot of stuff.
But that's not possible! I learned from the environmentalists how everything evolved in its own little area. That's why there are so many more species than we thought - they may LOOK alike but they evolved separately in their low little areas (like the Spotted Owl in Oregon not being the same Spotted Owl that's so common in Northern California). The ONLY thing that interferes with that totally local evolution in man - going around place to place, bringing their cars, boats, planes, and horses and spreading species to areas they DON'T belong in, and invading the virgin environment. /sarcasm.
Yup and the orange color is iron oxide (rust) that 'fertlizes' the gulf and causes algae to grow and suck all the oxygen out of the water and kills the fish.