Thanks Steven for the reply.
I guess it's possible it could be a CRS, I just find it really highly unlikely. In the tank next to this one I had some CBS that gave birth around the same time. They look like little CBS and they've grown up at a normal rate. If this unidentified somehow grew about 10x faster than normal shrimp it could work out. There's no red or white at all on it though.
I took a few more shots of it over the weekend. I included a few with it next to the blue rili and CRS for comparison. Also, this might be hard to see from the photos, but the eyes are a solid black, so it's not like a blonde OEBT.