Every single coin is going down in the list. I have never seen like this where every single coins go down. I have seen where most of them were down but at least 10 or 20 coins were up.
But this is the first time where every single coin is going down. Did it ever happen before?
It happened a lot of times in many different reason, I remembered it also happened when China announced that they will ban all cryptocurreny exchanges from their country few months ago. But this time the reason is that investors decided to get their profit after dramatic increase of most of the coins in the market specially Bitcoin. Because if people did not sell, some altcoins will increase and the Bitcoin price will drop. Anyway this is expected to happen after Bitcoin reaches $10k, but nothing to worry because it creates an opportunity to buy discounted price of Bitcoin, and it will recover for sure.But this is the first time where every single coin is going down. Did it ever happen before?
Tether is up, lol 
Tether is not much affected because the price of this coin is based on the value of US dollar. 1USD = 1Tether