Hi Sebastian,
Not necessarily. An EA can perform well and be profitable of any length of time. Sure, there will always be unprofitable periods, but we don’t know when that will be. It could be tomorrow, it could be in a month. So, the best thing to do, is to continue analysing the performance of the EAs in current market conditions, and if the EA fulfills the criteria you have set, there’s no reason to believe it will become unprofitable immediately after it performed well. However, it is still advisable to keep an eye on your live account, and if the EA has a few consecutive losses, remove it. That’s what I do.
Ilan