So i got a mated pair of clownfish a couple days ago and they where doing fine, swimming all over the tank and seemed happy, today i added a feather duster and cleaner shrimp and now the male clownfish keeps swimming up right next to the glass, it doesnt look like he is rubbing on it. it started abotu an hour after i put the duster and shrimp in the tank. is this normal, should i be concerned? Please someone help.