what do flatworms do in a tank?

AEFW are the only bad ones right? what do the rest of them technically do in the aquarium?

if you dont want them, what eats them?

 

There are a few wrasses that will eat flat worms.

 

yeah i have heard that... but do the flatworms actually do anything to the tank that could be negative?

From research i know they eat smaller protozoans, bacteria, and other microscopic organisms... does this include zooxanthellae in corals?

 

From what I've understood, their only major dangers are a mass dieoff (releases a toxin + normal pollutants into the water), and the potential for them to live over your corals, blocking out the light. Either is pretty much limited to a very large population of them.

 

Not that I am aware of but they can smother a coral

 

I've heard they can populate very fast and block corals from receiving light, but other than that they are okay. I have a few and they aren't a bother.