Just in case anyone wonder. Yes it is true. Most of the time when Bitcoin go down, Dogecoin goes up. When Bitcoin goes up, sometime Dogecoin goes down, but not always, sometime it goes up with Bitcoin. More often than not, Dogecoin goes up when Bitcoin goes down though.
Why? My guess is that, there are a lot of Dogecoin out there. These are the people whom held on to their dogecoin waiting for the right moment to convert to Bitcoin. When Bitcoin price dropped, people whom are holding on to Dogecoin sells their dogecoin to convert to BTC, as they will have more BTC in their possession. Holding holding BTC yield better advantage on cashing out to hard cash, easier that is, because today not too many exchange have direct Dogecoin to USD or cash.