Altcoins that have no strong fundamental and good developer will turn to dead/shitcoin the ico in year 2015 are difference to 2019 if you want to invest in cryptocurrency make sure you check the whitepaper to know its goal dont put all your money in one investment it better to split to 2 - 3 altcoin.
Holding for long term is one of a consider strategy in this kind of situation because we are in a stage of bearish we cannot predict when the bull run will back.