In fact, there are many reasons and no one knows exactly what the reasons may be for this. We seem to have begun to forget that the market is unpredictable, and if now we are in decline, then literally in a week everything can change. And this often happened in history, we just forget about it immediately, because everyone cares only about what they can get now from their investments.
The high volatility nature of cryptocurrencies never allows us to find an exact entry or exit point. This is where majority of the traders are trapped but those who have spotted the exact entry point would always have profits if they hold enough with their immense knowledge.
The markets would quickly go down as well as it might quickly get pumped so we should never expect stable returns at least until we gain some experience and learn how to spot exact entry and exit points. Many altcoins have turned red which might be because of the price pump faced by bitcoins as it usually makes most of the altcoins follow the opposite trend. But once bitcoin stabilizes, we can see altcoins growing back again.