if you are looking for an investment, specially short term investment then there is never a fixed answer to this question. today it is one altcoin and tomorrow it is another altcoin getting pumped and giving investors profit in short term.
for example now
litecoin, PIVX, Ark are the coins that i know are getting pumped.
if you want to day trade (earn profit day by day) then those altcoins with high daily volume are an option. but it is hard and scary to get into an altcoin which is in the dumping phase because you will lose money without a doubt.
for day trading go to bitcoin instead. or day trade on altcoins while they are getting pumped.
TLDR: get out of altcoins after the pump is over or die trying
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