Little pests - can you tell me what they are?

I had an unfortunate hitchiker on one of my corals about 6 months ago, and slowly these little square brown flakes have multiplied until they've gotten to the point they are smothering some of my corals! I posted a picture of them below. Can anyone tell me what these things are and/or how to get rid of them?

Thank you,
Chad

 

Those would be flatworms.

http://www.chucksaddiction.com/hitchworms.html

I believe the flatworms are at the bottom of the page.

 

*bites lip*...damn there's a lot of flat worms..

 

Are they red or brown.... two very different specimens. Brown not so bad. The reds are toxic. Flatworm Exit will get rid of them, but follow the directions to the letter.

 

i would treat them with flatworm exit, regardless of the toxicity of them....as you can see, they become toxic by shear numbers