I am starting to get worried. All day our large black dalmation molly and our giga. gold balloon molly have been bullying our black balloon. It's odd- first time we've seen it happen and the large dalmation has been pushing it around, herding other fish away from it, and slapping at it with its rear tail. For HOURS now! What is odder, our small gold balloon which usually swims around freely has been hiding scared for a couple days. No change or additions in tank. Any advice?