Aulonocara stuartgranti "Chitimba Bay" is a member of the Stuartgranti complex of Aulonocara species and is often sold by the trade name of "White Tip Masoni", thus a synonym for this fish is Aulonocara masoni. Another designation for this fish is "Chitimba Deep".
The Aulonocara species flock are often called "Malawi Peacocks" generically.
No matter what you call it, this is a nice looking peacock. Males get an overall royal blue metallic cast with an impressive white or ice blue edging to the dorsal fin. Males also have nice orange ventral fins, too.
Females, like most peacocks, are drab with an overall grey-tan case a few markings.
You should not keep Aulonocara stuartgranti "Chitimba Bay" with any other Aulonocara species as it may interbreed.
About eight to ten years ago when first introduced, this fish caused a considerable stir in the hobby. If I recall, a variety of fish were exported as "Masoni" but not all of them matched the description we know today.
The common name for this fish is The White Tip Masoni