Hi ulka and and welcome!
Your fish is a Xenotilapia sp. "ochrogenys ndole" - does the male have black in the outer part of the ventral fins, like this one?
If it has, it's from Ndole Bay - in your last photos it could look like it has some indistinct black in the ventral fins. If it doesn't have any black in the ventrals it could be Utinta or Mzuri, but I can't say for certain.
All the best, Thomas