What is this spot on the eye?

[Flipturn88]

My pajama cardinal seems to havge developed a small white spot on the surface of his eye. It sticks out straight and is the size of a pencil point. He's eating fine and i can't see any other unusual symptoms.

 

Does anyone know what that is?? How could he have contracted it? I added some fish and rock last night, so maybe that could have stressed him. None of my other fish are showing any signs as of now, except occasionally they'll open their mouths like they're yawning...?

 

Also, could the flash of a camera cause that (I was tanking some pictures). Thanks in advance for your help.

 

~Kayla