Agreed.DJRansome said:With a shorter tank I'd try to go smaller and more peaceful than usually recommended for a 55G. Smaller would be 6" at maturity or less. Aulonocara baenschi at 5" would be a smaller peaceful peacock. Lemon Jake at 7" would be a large aggressive peacock. Browse through the profiles and review sizes and temperaments.
Jakes are almost too rambunctious and this includes the Lwanda and Swallowtail. -Ideally, the Swallowtail should be kept with a quiet group. It's fins are amazing, (hence the name Swallowtail) but in a small community tank, it will not become the flashy specimen that you see on the internet.
Rubescens and German Reds are pretty much the same fish; all originate from the Aul. Chipoka. If you want color, it's best to stick to just one male of one variation.