A little riddle for you guys

I'm just going to start off by saying sorry. There is no reward for solving this riddle aside from the satisfaction.

Joe and Bill go fishing. They both catch fish. If Joe gave Bill one of his fish he would end up with half as many fish as Bill. If Bill gave one fish to Joe, they would end up with an equal amount of fish.

How many fish would each man have before any theoretical trades?

Now I'm kind of slow so it took me about 25 minutes to come up with the answer when this riddle was told to me. Let's see if you can do better!

Edit: ok you guys got that one pretty fast... so here's a bonus riddle if you're interested:

What can go up a chimney down, but not down a chimney up?