I would say an Apistogramma sp steel blue but i could be wrong.
I was looking at pictures and most seem to have a big spot by the tail like this one and yellow fins some with blue specks on which also fits this so if its not them its something every similar.I would say an Apistogramma sp steel blue but i could be wrong.
Thats what I was going to say as well but not 100% how to ID them.
Wills
If thats what you brought it as i would say it is then. Have you only just got it? it looks quite stressed out so it might just be a little off colour until it settles in.I got it as a steel blue but does it look a bit yellow?