Holding Ethereum is a good Idea for long time investment. other wise we cant earn profit within short term by trading Ethereum. within 2 years it is grown 40 times and holding a major position and acting a major role in crypto currency industry
When you have many Ethereum alts, you can exchange some of them for the other altcoins. In case that you have 2-5 ETH, you might probably hold them for a long time to get the better profit with the time.