Not always. Hooks live just outside of the stomach (I can't remember my anatomy right now) but can cause black poo. The redder the blood, the closer to the anus the critter is bleeding. Depending on diet and excersise and metabolic rate, dogs usually take 12ish hours to complete a digestive cycle. If you have one with a longer metabolic rate, you can have black poo from parasites. Not usual but does happen. I'm always amazed at the number of medical people that will tell you hooks WILL show on a fecal every time when it's simply not true. They only show when they shed and that's about every 6 mos and you just have to catch them when they do.
I want to apologize for answering so quickly and not asking for more information. I should have known better. Drug use can drastically alter any dx and I should have asked about diet, habits, and illnesses first. I'll be more careful next time.
I hope he gets to feeling better very soon.
