Traveling during the holidays is stressful, but the staff at Denver International Airport will restore your faith in humanity with the story of a fish named Cassie.

Fish can't fly. I mean, you already knew that, but like, they can't fly on planes either, or at least not on Southwest Airlines. While TSA gives fish the 'OK,' the airlines does not. CBS Denver shared the story of a Colorado college student who was forced to leave her Beta fish, Cassie, behind at DIA so she could board her flight — but it doesn't end there.

According to USA Today, staff at DIA found the surrendered Beta in the lost and found and took it upon themselves to care for Cassie, and eventually reunite fish and 'mom.' DIA even wrote her a letter from Cassie, which read: