Take hammer out of tank and scrape off aiptasia in one piece if can or inject into mouth with boiling water / lemon juice/kalkwasser I read.
Best to get hammer into little container of water to do this.
Most will say if got one then maybe more in tank and can get aiptasia eating filefish or aiptasia eating nudi's,( after aiptasia gone the nudis will die as that's their only diet)
Can inject them in dt also but turn all flow off for little while .
I read aiptasia x spreads them ,alot say.
Then there's f aiptasia which puts like a blanket over them.
Also peppermint shrimp eat them but get the correct ones.theres about 6 shrimp that all look similar and some eat them and some dont apparently, some say peppermint can eat some corals so there's that also
I've got a few on a zoa rock,keep meaning to remove rock and the 4-5 aiptasia but been 6 months or more now and only see same ones on the rock they came on.
But I've got a cbb fish so that could be eating Any that sprout up .
But they don't really bother me that much tbh,but that's just me.
Good luck