It aint no firemouth, it's from the genus Amphilophus, which species a bit hard to tell (there are dozens of species in that genus) that all look similar when young.
Modest_Man;5019820; said:Goodness. It's a juvenile Amphilophus. Most likely it's a midas/red devil that hasn't gone through a color change yet. Not a flowerhorn, and not a firemouth.