i can tell you about that problem..i just finished treating 2 tangs for it..it took a series of formalin dips, but i finally nipped it!!! the fish still have some scars where the pods werethe only other thing i can think of is something called 'crab pits'. dealt with these things once i believe. they are actually a small crusteans that dig into the fishes body. very difficult to remove from the fish... but the symptoms sound a tad bit different.