When the nitrate spikes, that means the cycle is over. Then i would take it out. Whatever you do, talk to us and the fish store. As sad as it is, most lfs
will sell u a fish that doesnt belong in a 30 gallon, just to get a sale. We, arent trying to sell u stuff, we want u to be sucessfull. What type of clownfish are you looking at? Other fish options are kauderns cardinals, firefish and royal gramma. Any other questions, just ask?