I wonder when the whole market dyed red but BCH increased sharply and the price of BTC fell sharply. Shark want everyone sell the BTC to buy BCH, then the shark will harvest the BCH and increase the BTC again.
Should I sell BTC now??
Well for me, it is not that surprising. Most of the coins from forks are getting in mainstream right after the release in the market. It happened to Bitcoin gold and cash which before be more indemand that caused the value of bitcoin to fall. I would suggest you on not to sell Bitcoin but rather wait since for the long run, Bitcoin is way better.