It came up somewhere here a while ago, that there may be 2 different variations of kribensis (pelvicachromis pulcher). I've owned both of these variations, one has a yellow, throat and operculum and the other has a red throat/operculum. Not everyone agreed 
I found this today, studies show that there are 2 colour variants that are somewhat dependant on environmental factors!
http://www.seriouslyfish.com/sex-ratio-in-kribensis-influenced-by-environment/#more-287301
I found this today, studies show that there are 2 colour variants that are somewhat dependant on environmental factors!
http://www.seriouslyfish.com/sex-ratio-in-kribensis-influenced-by-environment/#more-287301