Clearly market with party opposite and partly identical patterns. I suggest there is only a little correlation, the congruence you see might be random as well.
Keep in mind the distortion in price through adjustment of both charts.
Apart from that I have identied a "visual" correlation between BTC and ETH and BTC and DASH which is often contrary.
The correlation factor can be used for adjusting your portfoliio before or when BTC is bearish already. Nevertheless when BTC is having a strong dip it will drg down alts as well.
This idea is not for placing buy/ sell orders, this is ment as orientation in volatile times.