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For example ETH has just had a bit of a pump whilst Bitcoin is has been up and down so I've traded some ETH for BTC hoping that I can catch a raise from BTC whilst avoiding any potential correction on ETH. I was wondering if this kind of strategy is something that many people have tried and had much success with or had any bad experiences with?
It's difficult on that way, not all the time Ethereum will pump and Bitcoin will do sideways, sometime if Bitcoin is dumping altcoins are dumping too, especially Ethereum and some large market cap altcoins.
The best way is to have both technical analysis for a pair you want to trade, seperate with Bitcoin and Ethereum for example. Sometime Bitcoin and Ethereum correlate, but the best to do is to have analysis first.