Caught a Crappie out of Grapevine lake a couple of nights ago and when I cleaned it there was 1 worm under the skin. Very small and rolled in a ball. You could barely tell it was there when cleaning the fish but when I pulled it out it was about 3 inches long. I'm not sure what they are but saw them for the first time in a video on Facebook. Anyone know what these are and more than that know if the whole fish is trash when you find 1 under the skin? The video I watched they were finding 5 or more on each fish. What are they and are they dangerous?