zoa eating nudi's

[cuz]

basically, does any one have a method for either a tank treatment, or a natural preditor? read that wrasses are hit or miss, also read about flat worm exit but that would meen alot of snails to hunt down meaning close to a teardown. Dips would be difficult as alot of my zoa colonies are on huge rocks.
any ideas are welcome but prefer hands on experience with them.