Just because it looks very much like a blue acara, doesn't mean you can rule out hybrid straight away. As you have no idea which genes are recessive and which are dominant. I'd still keep a close eye on the tank.
The second picture was taken with flash, so the colours will be brighter as there's more light to reflect back. A picture without flash would be a closer representation of its true colour (which is possibly what the first and fourth pictures are).
The second picture was taken with flash, so the colours will be brighter as there's more light to reflect back. A picture without flash would be a closer representation of its true colour (which is possibly what the first and fourth pictures are).