That depends on the nature of ‘bitcoin being bearish’. Overall, we see a high correlation between ALT/USD valuation and BTC/USD valuation. With very few exceptions in the overall cryptocurrency market cycle, we do not see many situations in which ALT/USD prices increase while BTC/USD price decreases over a noticeable length of time.
In our experience, we notice that ALT/USD prices perform well when BTC/USD price is appreciating. After a positive movement in Bitcoin’s price, we can see money flow into the altcoin sector and outperform Bitcoin briefly. However, once that cycle ends the money flows back into Bitcoin and Bitcoin either takes a leg higher, in which case your money is best held in Bitcoin for that time, or Bitcoin depreciates and Altcoins depreciate much faster.
Therefore, trading Altcoins needs to be nuanced, however in practice, we rely on our algorithmic system just as with any other cryptocurrency or currency pair. In general, it is much easier to trade and think in ALT/USD value and not ALT/BTC value. In practice, access to the margin and liquidity to do that can often be quite challenging, hence the USDT markets.
A general rule of thumb, if Bitcoin is sideways or appreciating rapidly, your eye can be on potential Altcoin trades. If Bitcoin is in a clear downtrend, Altcoins are best avoided, at least at this point in our market.