My fish are fighting!

Question
I have 2 oscars that are roughly the same size in a tank with another Cichlid that the fish store guy told me they would be OK with.  It is not one of the aggressive African Cichlids.  The two Oscars first started fighting: locking lips, pushing each other with tails and shaking.  Then one seemed to get spooked and everytime the light came on he got drunk and went on his side.  The other Oscar would almost push in in the corner behind a plant where he spent most of his day when the light was on.  The one Oscar then seemed to dominate the tank and occasionally chased the other fish around.  Then, the other day, the Cichlid had it and started kicking butt!  He had both Oscars pinned in the corner and would periodically take shots at them.  Both Oscars were getting pretty beat up so we put a separater in.  The Cichlid is a mainly white fish, sort of roundish and the same size of the Oscars.  It has a pink tale and when he is aggressive or challenged he gets real black features and almost has black stripes like warpaint.  There is also a very small Fire Mouth and a Gold Fish that was the last of 20 to survive and is not too big to eat.  The two smaller one are left alone.  They are in a 90 gallon tank and the 2 Oscars and the Cichlid are each about 8 inches long.  Any help?!!

Answer
Dear Zac,
Well, I'm sorry to say that keeping cichlids is always a hit-and-miss sort of thing like you are experiencing. Sometimes they get along extremely well for life then oftentimes they will not tolerate one another for more than a second. And of course there are instances where one decides he wants to rule the aquarium after living quite peacefully with other fish for years. That's one of the troubles with keeping cichlids together.

The best thing I can say for your to try is help your Oscars, Firemouth and the unknown cichlid established territories (hopefully) by literally dividing the aquarium up with tall plastic plants (  be sure they are secured-cichlids will uproot them) as well as large pieces of driftwood, fake wood, stones, and large caves. It is said that it helps to provide "visual barriers" for a aggressive cichlid tank and I've had some sucess with this also. It does help to have plenty of territory dividers in the form of rocks, stones, plants and other decor.

Oscars are especially sensitive fish. If something goes wrong or they do not like their enviroment, they will sulk and hide like you are seeing the one do. Many oscars do not appreciate bright lights. Unfortunately he may eventually have to be removed if he proves to be too timid. Giving him his own aquarium would be great!

You can try adding territory boundaries in your aquarium. But I simply cannot guarantee it will work. Like I said it's a trial and error, hit-and-miss sort of thing when it comes to mixing cichlids. To tell you a very honest truth you may not be able to keep any of the cichlids together in your 90gal. Not to say there is no hope just keep in mind cichlids like oscars sometimes just don't want to live with anyone else. Actually I have found with the cichlids that I have kept--that they thoroughly enjoy being by themselves in a tank of their own.

But for now you can only try your best to provide plenty of large caves, territory dividers, tall plants and visual barries. And hope for the best that everybody straightens out. Dont give up hope. I still see many aquarists whom keep many different cichlids together with few problems.

I really hope this helps and best of luck!!!
Best wishes,
Karen~