Because this worm was alive, it was wriggling non-stop and the images are a bit blurred, but clear enough to see the head parts. On the picture at the left, just at the tip of the pointer, you can see the two retracted "fish hooks" in the abdomen area, the appendages that extend beyond the head and attach to the fish. These hooks securely anchor the worm to the fish, and are the reason they must release before trying to remove the worm. A dab of turpentine is usually good enough to cause the worm to release its grip. A knife can then be used to scrape the mucous containing the micro fluke from the fish's body. The smaller appendages surrounding the mouth are the sucker parts.
The inset is an isolated image of the hook anchors.