Back in the DARK ages, when it was not only acceptable but also a common practice of using fish to cycle a tank, I used Black Mollies instead of Damsels. They produced babies galore and ate the heck out of the algae. Eventually I was left with only one, he was HUGE and was a bit of a punk in my tank. So.....he found his way back to the pet store and was Trigger food.
IMO....they seem to poop alot. Of course, I suppose if they are eating a boatload of algae, one thing causes the other.
I currently have one in my 235. His fins stay beat up all of the time. He will heal up and in a few days looks like ****it again. I don't see anyone picking on him, so not sure what is going on there.
I do agree with the earlier posting.....looks kinda odd to have one in my reef set up, but back when I had FOWLR, it didn't seem to be as strange.