Red flatworms

Hey everyone, my college has a 150 gallon tank that I may(or may not) be taking over. The problem is the display glass is covered in coraline algae, and what I believe to be flatworms. I'm a newbie to saltwater, but a huge freshwater fan. I have 2 questions
1. does anyone have a zoomed out picture of a flatworm? There are a ton over the glass, and it really just looks like a ton of small reddish lines. I can't tell if what I have are actually flatworms or not by comparing it to pictures I find, but they're taking over the display glass.
2. Will mandarin dragonets eat flatworms? The tank is 150 gallons, and the only other occupants are a black clown fish, and what I believe is an orange tang. I need to make sure that these fish are compatibile with a mandarin dragonet, but from what I remember reading a few years ago, 150 gallons should be plenty big for a mandarin dragonet to have enough copepods to survive, and if it eats flatworms all the better. If it is the case that they do, I may just leave the flatworms in the tank until I can get enough copepods in the tank to keep a dragonet(there may already be enough in the tank it's pretty established, just needs some maintenance).
Thanks!

 

Checkerbox wrasses eat them. You might want to ask Evolve since he is the wrasse guru.

 

Melevsreef.com - Flatworms | How to eliminate them!

And google Red Planaria.

 

ah thanks, for some reason googling red flatworms only gave me zoomed in pictures, but planaria worked quite well. Turns out that's what it probably is