Yeah it's a grey I also found 2 grey's this summer when they were sitting on top of my front door lights eating the bugs at night lol. They're pretty amazing frogs. Catch some moths and watch them fly across the tank to catch them. They're really quick and precise in their attacks it's awesome. I just wish they didn't pee on me so much lol.

From what I can see it looks like a female (skin under its chin is white with no black dots).