Sundays mean E!’s got an all-new Keeping Up With the Kardashians and this week, Kourtney and Khloe Kardashian have a doozy on their hands.

In the upcoming episode, the sisters deal with the passing of a beloved family member.

Who?

Little Mason‘s goldfish, Pebbles.

“This is the exact reason why I don’t like pets because they die,” Kourt explains. “It’s very sad and tragic.”

“The number one reason why I’ve never had a dog or anything is because when I was little, my dog died and it was so heartbreaking for me and Kim.”

How will the Hollywood mom explain the loss to her son, or will she try to spare him the pain?

Watch the video above to find out!