Just as a note, next time you get another new fish, I would quarantine them first before combining with your other fish. It's just not worth your time having to deal with health issues as a result of transmission from the new ones that have them. A rubbermaid tub makes a good compromise if you are not allowed to have another tank. Always have a spare heater and sponge filter to go with the quarantine set.
If you are not prepared to house this fish separately (once it settles and starts attacking the rest, which is a hit or miss anyway), then asking for credit with a nearby store or even a friend is not a bad idea at all. They are cichlids so they're bound to behave differently.