Highly Aggressive Cichlids

[enjoyyourbear]

Regardless of what he really is, I have a feeling my fish is going to turn out to be something extremely large and extremely aggressive. At some point I'm going to have to get a 75 gallon aquarium as a result.
I'd like to know what he could go with if anything at all.
Do highly aggressive fish go with others? Could a Jack Dempsey go with anything else? What about an Oscar? Terrors? Convicts?
The biggest tank sold in our store is a 75 gallon. Let's say somebody wants that. What extremely aggressive fish could that person put in there?
At our store, Red Belly Pacus are labelled as semi-aggressive, yet due to their size, tankmates are extremely limited. What could exist with them? Whats the minimum tank size for them?
Does an 18" fish have to be by himself in a six foot tank? That may seem like a stupid question, because he takes up over a 6th of the length, but I get a lot of questions where I work and I'll say "I don't know," if I don't know for absolute positive. And I hate it, so expect lots of questions out of me. Thank you in advance for putting up with them.
I could look all these things up, and I probably will right after this post, but I'd really like to know from people who have had experience with them, because not all fish are the exact same.

 

[sogreene]

Regardless of what he really is, I have a feeling my fish is going to turn out to be something extremely large and extremely aggressive.

What he is will determine what he can go with.

I have lucked out with Jack Dempseys, though they should really be species only, as should oscars, IMO.
I have two juvenile (6 and 8 mos) jd's in my 125g african cichlid tank, along with a territorial pleco... (yeah, I have no explanation for him...he's always been this way-even before the africans)
We will probably have to move the JD's into another tank when they mature.

My parents had 2 large oscars, and 3 very large angel fish in a 150gal when I was little, although I don't know if this would be common practice or just their own luck.

 

[wemby088]

Pacu`s are schooloing fish and prefer the company of there own kind. A 75 is way to small for a pacu nevermind a few. These fish grow up to 2 feet and tend to be more aggressive if alone. No one can tell you what will get along with a fish that you do not know what it is. For example if you have a midas it will kill whatever you introduce. If you have an african then south and central americans are a no go. You should have someone ID your fish for you and then ask a question again. for larger and much cheaper tanks try glasscages.com.

 

[SeriousDude5]

Let me tell you my story I have a 5" bleekeri in a 90 gallon tank. He is not even full grown recently he killed my 7" oscar and began attacking my 6" tin foil barbs. I put a divider in to try and save the oscar, but it was too late infection won. The two of them actualy got along well until about two weeks ago then the bleekeri became very teritorial. Now without the oscar I think I will remove the divider and maybe give the two tin foil barbs to a store. Soon my tank will be just a bleekeri and a pleco . Lets look on the bright side the water should always be prestine now!

In conclusion, it may not be neccesary to house a lone fish in a tank. But, if they are teritorial or just a jerk, your pretty much screwed. I had an oscar green terror and jd all living together fine previously.