I have two Dwarf Gouramis in my 10 gal community tank. All of a sudden one of the gouramies has chased the other into a castle and does not let the other one out. He does this all day and night. Is this normal? From what I have read is that they are a peaceful fish and will even swim in pairs. I do not know if it makes a difference but one of them is a red gourami and the other is blue. Thanks for your input.