Found the culprit!!!

[Dactyl]

im from cali. sundial snails come in all the time on zoanthids at the wholesalers out there. also all other sorts of critters. i do miss getting the 'surprises' which comes from getting livestock straight from the indo-pacific. btw ludwigia, those green zoos i got from you are completely taking over one of my rocks.

 

[Ludwigia73]

That's a good thing, I hope... If it's the green rim, be sure to segregate that rock a bit so it doesn't take over the tank. Awesome zoos though, huh? Great bright color!