Always remember that the best cryptocurrency to invest in when the whole market is down is the one at that time which has the highest trading volume in the 24 hour period this is not necessarily bitcoin but can also be lite coin or iota or any other but this is the trick.
if there is a certain drop and a rise in prices in a short period, then it can be very easy to navigate in trade. But if you take into account the current situation, then a long time the market in a very bad condition can affect some coins and they then may not raise their prices at all.