Haha, thanks! Actually, as far as I know, they aren't actually related. The bigger, feisty one is 12 years old, and the slightly smaller one is about 7 years old. I got hem in the same city, but from two different pet stores.
However, they fight and cuddle like a married couple.
A recreation of that video is what I see every morning

They get so pushy that they've bitten my fingers numerous times and almost jumped out of the tank when I made the mistake of looking into it from the top.