The BTC has made history today and broke its all time high record. It is currently trading around $ 20500 to 20600. BTC Dominance Index is around 65% which is very High. I personally think that it is the Right time to take entry in Good Alt coins ( Ranking from 2 to 20 on coinmarketcap). I believe that History of 2017 will be repeated soon. We will soon witness Huge rally in Alts. It should happen when BTC will stabilize around current levels and BTC dominance Index comes down to below 60%.
There are a lot of altcoin to buy you only need to make a proper research to that altcoin before investing, some altcoin will not refer to bitcoin they have thier own way of making the price stable even of bitcoin is down. Just select good altcoin and always use an amount that you can aford to loss.