Pet Forum / Aquaria / Marine Reef / December 2004

The orange colored one is a red acoel of the genus Convolutriloba. It
is a common reef pest; not exactly dangerous but unsightly. Search for
"convolutriloba" or "red planaria" and you'll get thousands of hits.
Flatworm Exit was, last I checked, some years ago, the substance of
choice for killing this worm, if it becomes so numerous you find it
irritating.

The white one is another acoel, I won't try to ID its, but it's a
predator of very small animals (copepods etc) and doesn't tend to cause
any problems or occur in great numbers.

If you have red planaria, you should try this method to
remove them:

http://www.melevsreef.com/flatworms.html

Marc