Whenever I trade and make a profit, does someone else lose?

For example, I've been watching an altcoin market for three years and knew that a certain currency always triples in value going from x to 3x in a couple of months. Having spare money avaliable I put some in to test the strategy and I'm close to my 3x at the moment.

My question is, whenever I trade and make a profit is there always going to be someone who's made a loss or is this an odd way of thinking? Could it be that these people are losing a small amount of money or that these people are buying a coin by going (I'll put 10% in that) so as to not really matter if it profits or. Loses as it generated a stable ish value.