I think that altcoins will rise after the fork, but nothing is sure with crypto. It is hard to predict the evolution of bitcoin right now. Short term, buying alts when bitcoin is rising is not a good idea. My strategy right now is to wait till November 16. If bitcoin keep rising after the fork the alts might follow the same path, but is it worth buying alts when bitcoin is rising? If you put a lot of money on alts you may be able to make some profit, but I don't think the small players will. My strategy is to buy the coin that you believe in and HODL. Always think long term.