Actually this is a promising opportunity, when the altcoin price drops, it's time to buy coins that have a chance to rise in the near future.
but be careful because we don't know the lowest price of the coin. Usually after bitcoin is stable, the altcoin will go up and we enjoy this moment. DYOR
I spent most of my USDT investing in XRP when it increased by more than 0.4 $ in June. After it reduced I still decided to retain this investment, because I felt that altcoin will be coming soon.