In your experience what fish help the most with controlling GHA on rocks? I've tried mollies but they have ignored the GHA and stuck to everything else.
When I got one to deal with my GHA it got shredded in the powerhead and resulted in ammonia spike. Be careful with overflows too. The powerhead that shredded the nudibranch was a reef wave 45, so kind big openings which may be why. The nudibranch was full grown, about 3 inches, and they can fit through small places.