Marbled whipray (Fluvitrygon oxyrhynchus)

Alongside an unspecified dasyatid ray.

@Rizz Carlton Fluvitrygon signifer?

Nope, I'm not fully certain that it could be one of the three species of fluvitrygon either. I was talking about the one you uploaded here.
Marbled Whipray (Fluvitrygon oxyrhynchus) - ZooChat

It's snout is very long to be the same species as the one I photographed. I won't rule out that it could be some color variant (If thats a thing) or some gender dimoprhism thing, but its still unusual.

@Rizz Carlton I suspect that it's the same fish species, but slight difference in snout length

@Fargusno lack of patterns is also telling, despite presumebly being the same age as the second individual. I'm also not aware of sexual dimorphism between the male and female.

It could be a sick or stressed fish, hence the lack of stripe. Would need to look more into that.