If you have Crohns activity in your colon the bleeding is most likely from one f the apthous ulcers that form with Crohns. Basically the ulder erodes down to there it
opens a vein in the colon wall and you may experience bleeding (sometimes quite a lot) for several days or more. Oher sources may be fissures or, less commonly, a filstula. Colon blood is red to bright red. Blood from higher up in the small bowel or even the stomach will be darker, often clotted, or even black, as it has had more time to pass through the GI tract and been patially digested. While bleeding is mroe common in UC, it's not that rare in CD. I would say if you have the one episode you reported and no more, you probably had an unlder pop a brief bleed, but that also means your disease is likely more active. So yes, the best course if bleeding is new to you is to tell your GI.