I am a 31 year old male and I bleed from my rectum when I use the bathroom. There is no pain and it doesn't show up on the tissue when I wipe. I drink plenty of fluids and workout regularly. I am careful not to strain myself. I am not constipated and the feces isn't hard. Any idea what could be causing this? There isn't a lot of blood and it looks kind of dark.

It can be anything from internal Hemroids, to polyps to fissures as a few examples. You really do need to have a physician diagnose this... it may be minor or something serious.

I am going to refer you to a doctor for this. Rectal bleeding may be benign in nature, but there are also some very serious causes. Only a doctor can diagnose you based on test results and a physical exam.