It is always difficult to determine what species this kind of cichlid is.
But it's definitely no peacock (Aulonocara) or something. :shake:
The following species are all quite similar to the one you have, the best thing you can do is to 'google' and compare the pictures you've found with the cichlid in your tank. It's not going to be easy cos they're all look alikes. Good luck.
Pseudotropheus sp. "kingsizei manda"
Pseudotropheus sp. "kingsizei londo"
Pseudotropheus minutus
Cynotilapia sp. "black dorsal"
Cynotilapia afra (Mara Rocks or Charo)
Labidochromis sp. "gigas pombo"
Metriaclima zebra either from Minos Reef, Luwala Reef or Zimbawe Rock.