From my memory, every time when Bitcoin went up, many of the altcoins went down because people wanted to climb on the Bitcoin rise. What do you think?
Actually altcoins picks rally with the Bitcoin check history on coinmarkecap take example of ripple and DGB. If the altcoin is strong and have some useful product or some promising upcoming product & if their community is strong then they can easily pick up the rally with the Bitcoin. Last year there were cases of some altcoins which got down because their team abandoned the project or because the cases of theft of funds.