Eth is just following the foots steps of bitcoin just like any other altcoins do. Its just a matter of how high or low is thier price are going. For example if bitcoin drops by lets say 30% in 1 day, other altcoins will also drop but with different percentage, possibly higher or lower. This happen most of the time. Another example, try to look at the price charts, if you look at the price of bitcoin dated february 6, 2018 and compare it to other cryptocurrencies, you'll see that almost all cryptocurrencies drops at the same date. Just follow the bitcoin thread you might get an idea.