Question from Mandy via email: I put one in with 3 balloon mollies and it picks on one of them, did I make the wrong decision about mixing the two? We've not heard of dwarf gouramis being aggressive towards other fish. We have heard of Gold Gouramis being aggressive toward their tank mates. There are many things that could be involved in this situation. Is the tank big enough for all of the inhabitants? If not, it could be that the Gourami is being cramped and causing it to be aggressive. Many fish will become aggressive if not given enough space. There are a few things you can try. The first option is to get another dwarf gourami (if you have enough space). Another dwarf may create a diversion for the dwarf you already have. The second option would be to return the dwarf to your local pet store if their aggressiveness continues. Hope this info helps!