In my opinion some coin that could be safe for trading is coin that has good fundamental and the volume is high like ETH, DASH, WAVES, LTC, NEO, XMR, NEM. Because if the price down from the price that you bought so still any posibility the price will going up later, just patient to wait for that.
I think that at the present time you should not trade altcoin, you can see that bitcoin prices in recent days are constantly fluctuating and adjusting constantly, which has caused the price of altcoin is constantly falling. and not recovered. Therefore, at this time the risk is very high, you can lose money very well, I believe the bitcoin trade will be able to reduce the risk for you.