This is not the right decision because as you keep away yourself from diversification, you are more prone to loose money as compared to those who have already invested in a diverse portfolio.  So do invest in altcoin as well irrespective of the price because there is always a margin of profit for an investor. All you need to do is to hold and sell at a time when the price goes up. The rest is simple and understandable process which is the fall in the risk to loose wealth.