tank over 1.5 yaers old had 2 cleaner shrimp ,no fish addons in a few months.have a few corals ,duncan,frogspawn ,zoas ,hammer candy canes .Fish yellow tang,clarki,scotter blemys,sailfin tang.and a black urchin ..
duncan is only new addition . I think culprit is either duncan or urchin ??duncan was closed ttight for 3 days! No other problems in tank.
