Get a red tail barracuda also how big is your tank??
If big enough and you want an aggressive fish that won't even tolerate it's own species try a fahaka puffer mean lil bastards get about a 18 inches mine killed everything on my tank and everything that moved including my tyre track eel my peacock my zigzag everything my friend had one and thought pirahana would be cool to keep with it that **** killed the Pirahanas just for the heck of it you'd imagine waking up to eels dead head on one side of the tank body on another if anything it'll kill the bass, arowanas,real gars since even the gars tolerate big fish with them fahakas won't