This thread mentions chromis and wrasses: http://reefcentral.com/forums/showthrea ... did=775013 This article mentions wrasses too: http://www.wetwebmedia.com/pestflatwrmanthony.htm I have no personal experience on this topic but I've read that certain chromis, damsels, scooter blennies, nudibranchs and wrasses all have helped with flatworms.