No worries and I will just post what I was typing just now:
First, I have to say that if Keno's gums are much paler then usual with this much blood loss, we need him seen urgently since that is a sign he is becoming anemic. And if left to get too severe, he may end up needing a blood transfusion.
Now in regards ***** ***** for bloody diarrhea, toxicity or gut trauma from something he ate would be a worry. Though we can also see this with viruses (parvo, haemorrhagic gastroenteritis), bacteria (ie salmonella, campylobacter) or protozoa (ie giardia, coccidia). We can also see this with ulcerations of the GI.
With this all in mind, we need to have a check with his vet to pinpoint which of the above is present as soon as we can. Any delay and we'd want to start Keno on a light/easily digestible diet. Examples you can use are cooked white rice with boiled chicken, boiled white fish, cottage cheese, or scrambled eggs (made with water and not milk). The aim of these diets is that they will be better tolerated/absorbed by the compromised gut. Therefore, it should get more nutrients in and result in less GI upset and diarrhea. Fiber (ie canned or boiled pumpkin) +/- OTC canine probiotics can be added to firm the stools quicker and try to rebalance the gut.
In any case, I've just seen your message and that would be best for Keno.