I once bought a tank from a guy getting out of the hobby, he had several nice fish and a lot of live rock that I wanted, so I bought it. The live rock was covered in majano anemones, 100's of them.
You can rid them easily without killing the entire rock.
There will be several people voice their concerns about this, but if done correctly there is no health issue.
So upfront, some corals have toxins and when boiled or burned they can release the toxin in a vapor and cause you and your household health problems, some are serious...so please take the appropriate precautions.
I've done this many times to get rid of pest corals like anemones, aptasia, and Kenya trees..
So, buy a torch, a small pen [emoji996] sized one like a benzomatic, and also buy a regular sized propane torch...they're not expensive. I'll include pics of one at the end.
Take your rock outside, and be conscious of the wind, because you don't want to breath in the fumes or smoke of the burning coral. Don't let your dog watch or kids, so they don't inadvertently breathe in harmful toxic fumes.
If there's no wind at all, place a box fan behind you so it's blowing the smoke or fumes away from you.
Now you can simply spot target each individual coral you want to kill, and go to work. It doesn't take long with the larger of the two torches. You want to be sure and completely burn the anemone until it's black and crispy or it can possibly come back if any small portion isn't burned.
This technique is easy cheap and quick, and best of all it works.
Be aware that tiny new anemones will retract into crevasses and you're likely to miss them, so be prepared to have to remove the rocks several times to get rid of them completely, so stack the returned rocks accordingly.
The rocks won't look much different after being burned, but may have some burnt spots, the cuc will eat any cooked coral, and coralline algae will soon cover the rock, and it will be back to normal.
It's always best to remove any good corals fro the rocks you'll be treating, but sometimes that's not possible. If you have a coral on the rock that you want to survive, you may need to dip it in a bucket of saltwater every few minutes while your spot treating it. You can also take some aluminum foil and fold it into a square and hold it between the good coral and where you're spot treating the pest coral. Also any pest near the coral you want to keep should be treated with the small [emoji996] torch so you don't inadvertently damage the good coral.
I hope this helps, and happy reefing.
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