Well, the bugs are so small that you can't see, but they move as fast as a copepod...they have no yellow in them like the acrobugs...they are all red. I mostly can only see them at night. At the side of the coral, where it's all eating away. is where they are at. They crawl up into the white part of the coral skeleton. I haven't seen them in the mouth. Just on the sides, but they get up so far in there you can't see them. I have tried several times to veiw them as close as possible with a flashlight, but these suckers are fast. I have them on no other coral. But it's not the flatworms. I'm going to try to see if I can't catch them through a magnifying glass tonight. But then again the flash light will scare them away. I do want to mention, which I should have earlier, I had a red open brain that I purchased the same time as this one that died within the 15 day garuntee period. I never did figure out what went wrong with it. It's tissue just lost color, and it spewed it's guts out and died. But this modern brain, you can tell something is irritating it because it's little shockers are hanging out around the edge of the tissue where it is being bothered. I have searched the internet for 3 days, and have been in a few forums and can't find no answers. I wish I had a manual digital camera.