One thing that is important to know when investing in Altcoins is that they are tied to the all powerful BTC. This causes several things to happen, when there is a run on BTC, if it out paces the alt coins, the alt coins will naturally drop as the money flows to the source generating the most income. However, once the run on BTC ends, those gains will flow back into the Altcoins theoretically causing a spike of reinvestment. Additionally, well performing Altcoins should increase in value as BTC decreases in value, creating a bit of a safety net, should BTC go down.
If BTC increases faster then the % you have in your holdings, then you are still in a positive position even if your holdings are now slightly in the negative range. So the thought here is, it is safe to hold, if BTC is increasing very rapidly, even though there is a mass sell off. If you can predict this, you might just be a Crypto.
If BTC decreases but your Altcoins increase in value more % than the BTC decreases, you are in a positive position.
Be wary if BTC is decreasing and your Altcoins are not increasing by a similar %. If BTC goes down and your Altcoin goes down, then you lose twice. So try to not let that happen.
Party on.