Is there any relationship between the two?
Whh must the fall of bitcoin after other altcoins?
Simply because altcoin is just relying from bitcoin. Most of the other coins are just made after bitcoin and if the price of bitcoin will decrease then they will do the same. It was just a vice versa.
I do not think much about it because I see it and I know if bitcoin price decreased altcoin will also decrease because Altcoin always follow its movement then than that if many people say Bitcoin lower altcoin I think it is wrong because Altcoin itself always follow the movement of bitcoin