She sure looks like an Opal to me. Her eyes are also gray-blue - which is the correct colour for eyes in Opals...not sure what colour eyes blue otters are supposed to have.
ETA: If you blow on her fur, does she have the described ring colour of an opal? It should be blue up top, and the intemediate ring should be tan/fawn. Hah, if I had my standard with me, I'd be able to see if Blue Otters have ring colour as well...but I'm not sure.
Thank you!! I am holding on to her shes out of one of my best show doe/ buck I was confused because her sister is soild blue her brothers are one opal and one black otter then her so I wasn't sure what color to call her.