i have a common clown in my tank now for about 2 weeks. just a couple of days ago i put in a hairy mushroom rock. the nxt day my clown had this small dark bump under his mouth looks like a gotee really. can anyone think what it might be. ive been trying for an hour to get a picture but my photography skills suck and i cant get a good picture. also he is very active he is still eating and is swimming around very spunky