Keyholes Fighting Question

Hi,

We are re-establishing a 55 gal tank and would like it to be a community tank (the tank was previously dedicated to a single large green severum). My husband picked out 3 youngish keyhole chiclids. We have had keyholes previously and never had any problems with them fighting. The new fish did OK for the first few days, then two of them started chasing and attacking the 3rd. I moved him to a smaller 10 gallon tank. Shortly after doing so, the remaining pair spawned.

The question is whether or not there is any way to have the 3 keyholes live in the same 55 gallon tank? It appears that I have two males and a female. We plan to buy other non-chiclid fish to add to the tank. Will this help to make them less territorial?

Oh yes, my tank does have rock work, a terracotta pot, as well as a few live plants. I tried rearranging the rock work to make more hiding places. When I added the 3rd fish back, they still chased him around.

Any tips? Am I doomed to having two tanks set up or getting rid of one of the males? I would really like to get all three of them to co-exist in the same tank if possible.

Jennifer