Freezing temps with outside goldfish

I live in SETX and the temps are gonna drop well below freezing over the next couple of days. My patio pond has 12 goldfish. Some small, medium and large. I went outside to check them and some are chilling being still some are darting around fast and then stop and kinda roll and float and then speed off again. It’s weird. I’ve read that that they should be fine. They have an aeration system and a pump with flowing water. I’m trying not to watch them to much because I’m freaking myself out. Some advice or tips or personal experience would be greatly appreciated.