If we explore more deeply why when the dominance of BTC goes down there are some altcoins going up, in my opinion because of the transition that investors make to buy certain altcoins, as we all know altcoins really depend on the popularity of BTC, if Bitcoin goes up altcoins also go up so Also on the contrary, if altcoin drops, it will also feel the impact, my current perception is that altcoins that don, 't affect BTC decline is like ETHEREM and Litecoin,
This is not always the case. Just when you look deeper, you will see that how fast Bitcoin's price changes also has a big impact. If the price of Bitcoin rises very quickly, investors are shifting their funds from altcoins to BTC and their prices are falling. This is usually a very short period, a maximum of a few days, and then altcoins start catching up with BTC, but it happen very often.