Looks like it could be a juvenile washed out syn but vieja can look remarkably similar at small sizes and adding on to that the crosses breeds floating around don't help .but I'd say syn
I'm leaning more towards fenestratus due to the length of the black running down the side of the body. The black on syns doesn't typically extend that far. Looks like a healthy juvie, post more pics as adult coloration comes in.