while you check your zoas for more nudis ... check them for eggs as well. they will be white, stringy, and mucus like. if you find eggs, suck them out with a baster or gravel vac. i had one once ... and i found it eggs on a new zoa colony that i bought 2 days before i found the nudi. you can also run fresh water (ro/di water) over the colony to remove any left over eggs.