Once these worms start feeding on a host fish they acquire pigmentation, which causes the appearance of black spots about the size of a grain of salt on the body and fin membranes . Worms that freely move about on fish, the spots do not always remain stationary. On light colored fish they are easy to see, whereas on dark colored ones they may go unnoticed at first. Fish will scratch up against objects in an attempt to dislodge the parasites, and if allowed to progress the fish become lethargic, loss of appetite and colors occur, rapid respiration develops, and secondary bacterial infections can invade damaged tissue sites.
