Normally I'm a pretty big fan of Astrena Starfish. They are free cleanup crew and while one or 2 do nothing when you have perhaps thousands they do a relatively good job keeping algae off things. There is some debate what they actually eat as far as thin film algae, coraline and even corals. I would say they eat all of the above although generally I don't have too much trouble with them and corals. I suspect they actually eat the slime off corals. After all if I have 1000s in my tank and I'm not losing corals they can't be doing that much damage.
The population lately has been getting out of control, I always take a few out with a weekly water change, sometimes I toss some back, sometimes I toss some outside. I decided to see just how many I'm getting...
