I wouldn't recommend getting a fish just because it's aggressive. In the long run you will just end up disappointed. I would get a fish the you like and that will live a long and happy life in the tank you have.
If you are only keeping one fish, than aggressiveness won't really matter. So don't limit yourself on that one attribute
You could possibly go with a single oscar, but that may be pushing it. You would have to really keep the tank clean/water changes.
If you are only keeping one fish, than aggressiveness won't really matter. So don't limit yourself on that one attribute
You could possibly go with a single oscar, but that may be pushing it. You would have to really keep the tank clean/water changes.