Hi,
I had purchased around $50 worth Etherium few months back.Now the Etherium price is very high.
I could make a profit of around $15... Is this the best time to sell.
Will long term investment be fruitful ?
It's up to you. But for my suggestion, as long as you already have profits, go sell them. It is very nice to take profits and you can buy again when there are dips. You should always think that you already have profits, don't be greedy.