My firemouths also had a jag n an Oscar a Texas n Dempsey w them. None of them bothered them either. From my experience unless its outright food the larger fish don't really pick w smaller fish. I think all fish are much more aggressive to fish their size. Maybe seen as competition? It's like an eleventh grader may compete with a tenth grader but they both wouldn't even consider bothering a third grader. Lol. No matter how tough that five year old thinks he is or how many times he pushes me, at thirty I just don't see a threat or response being necessary lol