Petrochromis sp. "Mtoto yellow"
This is a mysterious Petrochromis sp. to me. Most of them at 2-3" (as the fish pictured) are the bright golden yellow color like the top picture but a few are the brownish color pictured below with a little yellow and a few more are in-between such as the middle picture. I don't know why the color variation. Either the males turn brown with maturity, both sexes turn brown in time or there's color variation within the species, I do not know.
I also do not know at this time what the maximum size of this fish is or how aggressive they become. At 3" they are not as aggressive as a 3" Tropheus but it remains to be seen once they start spawning how aggressive they will become.
This fish should be available on a regular bases in the future.