There is a lot of confusion regarding the red peacocks - Aulonocara "Ruby Red" (Rubin Red), Aulonocara "Rubescens" and Aulonocara "German Red". Part of the confusion is due to their names, no doubt.
First of all, these fish are not hybrids. Sure, a few may be hybrids, but this is the exception and not the rule. These fish were developed by line breeding a single species: Aulonocara sp. "Stuartgranti Chipoka". In the lake, Aulonocara sp. "Stuartgranti Chipoka" demonstrates a variable color variation, ranging from sunflower yellow to fire-orange. Capitalizing on the occassional orange male, Ruisbroek in Maassluis, the Netherlands, developed a red strain by selecting fry that had more and more red. Eventually, he turned out a very red peacock - the Ruby Red. It was dubbed "Rubin Red" simply because Peter Rubin was the first in the United States to import the strain. As you can see then, this fish does not constitute a new species - being that they are still Aulonocara sp. "Stuartgranti Chipoka". The new name is a marketing gimmick, but a justified one inasmuch as it alerts the hobbyist to the red body color.
The German Red variety was developed through selectively line breeding the darker Chipoka species as well. The name escapes me at the time of writing this (and I can't find it either), but a breeder in Germany was responsible for this strain - hence the name.
There is some confusion (in my mind at least) as to the origin of the Rubescens. My understanding is that it is the same fish as the Ruby Red, but was resold by a farmer in Florida who re-named it after himself.
So, are these fish new species? No, absolutely not. Why then are they sold under different trade names - Rubescens, Rubin Red, German Red? Are there any real differences among them to justify it? The differences are subtle. The only differences might be intensity in their color, but this can vary within a single batch from the same parents and could easily be affected by diet as well. They're sold under different trade names because these are the names their breeders gave them. So, what do I call my red peacock? Whatever you like: Fred, Pete, Sam or anything else that suits your fancy. The point is that any differences among the red peacocks is either subtle or imagined and getting the proper name is a bit silly unless you're breeding and reselling them. In which case, you should only get your peacocks from a reputable source, someone who can garauntee their strain origin. But remember, all these peacocks are really a single species, bred from a single geographic location.
What is line breeding anyway? Well, as I alluded above, line breeding is the selective inbreeding of a single species. This is carried out by an observant and dedicated breeder who picks out fry possessing sought-after characteristics. In this case, our breeder would separate out promising fry or progeny demonstrating the most red. These are then inbred (or bred with the parents), again selecting for the progeny who have more and brighter red than the first batch. Females are also selected if they possess "more than normal female coloration." This process can take years and the breeder has to keep very good track of which fish came from which and where he or she is going with each fish, but in the end, the breeder will have developed a show class peacock with intense red.
I hope this has cleared up some confusion about the red peacocks. In summary, they are not hybrids. They are all belong to the same species: Aulonocara sp. "Stuartgranti Chipoka". And any differences are really inconsequential unless you're the one trying to line breed them. □