mexican red rumps are cool. Mines only 1.5 inches right now. Here's a little advice for them, as I'm sure you know already since this was posted a few months ago. They really enjoy digging, lol. So coco fiber substrate isn't always the best for them. They'd prefer something that "sticks" a little more; so the dirt doesn't collapse in on them whilst tunneling. I hope you're enjoying it! They are very fascinating creatures!!I've ordered a B.Vagans it will be here on Tuesday