Identification Please

Red Flatworms. I have a ton of them in my Xenia Scrubber tank. I have heard they are not too bad. I have none in the main 75g SPS display due to the 2 Leopard Wrasses.

Red Oscellated Dragonettes tend to eat them as well. I added one to the 29g Xenia Scrubber a couple weeks ago and their numbers are dropping.
 
Yup, red Acoels (Convolutriloba spp.)--not really considered a true flatworm anymore--cool, but troublesome nonetheless. If biological controls fail, there is also a product called Flatworm Exit by Salifert that works well. Just be sure to follow the instructions--I can't stress the pre-siphoning of worms enough if you decide to go this route.
 
The problem is that they release toxins in the water when they die, so getting them out of the tank is the best thing.

I've tried flatworm exit and it worked very well.

I hear that wrasses eat flatworms as well.
 
The leopards and coris wrasses work very well on natural control of these flatworms. I don't have any in my system and I have several wrasses in my DT.
 
AquariaCentral.com