very small, orange, rectangular specks...are alive!

[pkmk]

I noticed small, square specks on one side of the tank. I thought they were flakes of food, or some algae. But, they are creatures! And they are multiplying. They seem to congregate and are on the glass, and they're really multiplying, and come in various sizes from tiny to very small (largest 2 mm). What could they be, how do i stop them. Need pics?
Please, help.

 

[Anonymous]

Without a picture my guess would be Convolutriloba sp. (Acoel Flatworms), they are attracted to the light.

Regards,
David Mohr