What are these...possible pest?

[kirkland]

Last night I noticed brown spots on one of our frogspawns in the white area between the soft tissue & skeleton. Today I sucked some out with a tiny hose and after the soft tissue withdrew, I saw these was also spots on the soft tissue & found one on a striped mushroom that was nearby. They do move because I could eliminate them all on 1 side then flip the coral over and there would be more on that side - sucked them out, flip and repeat. Is this a pest? Are they bad? By gently shaking after the coral had closed up, a few came off in the water as well. It almost seemed as if they slowly scoot around? They look like tiny flat blobs. We have other euphyllias & elegances in the tank, not sure if I should be worried or not?

 

[travis_]

flatworms I think, I have them too

 

[xrayrider]

Flatworms! Easy fix.

 

[Pentagona]

In a lot of cases simply doing a large water change in addition to your normal routine will knock them down.