I know i can do a quick research but give example of when btc was in bear market, the 2018 beginning of year, and some alts still moon ?
any example
There are many factors regarding the rise in altcoins that occur when bitcoin is experiencing a decline. and the altcoin average in terms of trading volume is still low. so it is easy to experience a high rise.
you can check on coinmarketcap :
https://coinmarketcap.com/gainers-losers/Nearly all that experienced high increases were new altcoins and also the market cap or trading within 24 hours experienced a high increase from the previous low. these things are commonplace and happen every day. Hype and Fomo were created to be able to raise prices. or usually their platform is launched. so even if bitcoin is in a bear market there will still be an increase in altcoins