id say either no more fish but you might be able to get away with the GT. the jag is going to get much larger than a gt and most likely be more aggressive.
i would say just the GT and drop the female con. Jags just get huge and can be aggro. look an greenterra's jag is is huge and with a bad personality it wold kill everything in the tank.
i picked up a firemouth, gt, and what i THINK is a jag today. they are all very small, about 2". they may not even make it but well see. ill get rid of the female con and the 5 tiny cons at the next water change.