Hide some dead fish in his room prefribly on a hot day. Or let the fish go rotten in a sealed container first then freeze them (this is more for your sake) take the lid off in his room and shove them under or in his bed once they defrost the true smell will arrive. Also any frozen insects you can get wich are still alive are also good for hiding onece they defrost and come back to life theyll give him abit of company.