im not sure if it is a legal fish where you live, but an oreochromis mossambicus xhornorum is a badass fish, super aggressive, they are invasive fish but are legal where i live, way to cold for them to breed and survive, when i first started in the hobby and i was dumb i had him with a flowerhorn, and even though the flowerhorn was very aggresive, that tilapia kicked his ass.