it is normal that all cryptocurrency price are dropped, no need to panic because some of big whale are stayput on their chair waiting for this moment to buy some and hold.
other says its because of chinese government who banned ICO but i think it is not the reason's why. maybe it has a effect but not too much or totally the reason, like i said it is normal to all alt-coins to drop.
We all know that cryptocurrency is a volatile market so something like this happening is not that new and because of bitcoin is in its corrective phase, other altcoins followed suit cause many are panic selling and maybe will get out totally to cryptocurrency or would just wait till price is going back up again. We can observe that price is still going down today and we don't know where is the bottom to this but of course there are speculations of where it is so for others who can take this fall, they will hodl and for others who panic, they get out. I think during this time, this is a test of who really can take the appetite of being involved in cryptocurrencies.
The idea is that veteran traders took profit when price is in ATH or almost high and then others followed suit and since it made the price go down, others panic sell and push the price down further. The announcement of China banning ICOs affect some altcoins thus it goes down as well and eventually almost all altcoins are down.