yup...it's not anything south or central american so definitely not dempsey or gt....it's some type of tilapia but not sure which one. Oreochromis tanganicae perhaps? never seen juvies so couldn't say for sure but if that's what it is be prepared for a huge fish...beautiful but huge.
Nile most likely. Oreochromis niloticus and unless you're expecting to see one properly labelled at a shop and not as some invasive contaminant or as a possibility for the night's meal at a market - then it's a pretty common beast.