So for short term investments I am assuming you want to be a day trader or at least sell out after a week and make a profit. If so you have to be watching the exchanges daily. Of course you have to consider the liquidation part. In my country, the only way you can cash out cryptocurrencies is by converting it first to bitcoin. So if I do this trading investment, ultimately I have to invest in an altcoin that would rise in value against bitcoin so I can buy more bitcoins and cash it out to fiat.