What you are describing with your dog is called colitis.
With colitis, dogs tend to have more frequent bowel movements, a sense of urgency, sometimes straining, and it progresses to mucus and even blood on the stools. The stools often start out a bit soft, or pudding like and become gelatinous, shiny and mucoid as it progresses. The colon normally makes mucus to help the stool to pass along, so when it is inflamed it makes a lot of mucus, and also can have erosions that lead to bleeding.
Colitis could be caused by a large number of different things. Examples are stress, dietary indiscretion (eating something she shouldn't have, like the fishy smelling thing), bacterial and viral infections, and parasites.
If a dog with no history of stress were to come in to my hospital, and we didn't have to consider money (so I could do all the tests I would want to do!) I would start with a physical exam and then a number of tests:
- fecal analysis to rule out hookworms, whipworms and coccidia http://www.petplace.com/dogs/intestinal-parasites-in-dogs/page1.aspx
- an ELISA test for Giardia. Giardia used to be hard to diagnose, but this test is fast and easy and accurate.
- a fecal culture (sent out to a lab) to check for Clostridium or other unusual bacteria. This test takes 3-4 days.
- fibre trial - I would start the dog on metamucil. I usually suggest 1 tsp per 10 lbs body weight given 2 or 3 times a day. Do this for at least one week.
- medication trial:
I would try metronidazole (http://www.petplace.com/dogs/metronidazole-flagyl-toxicity-in-dogs/page1.aspx) as a first line treatment but there are a number other drugs that can be helpful too:
Panacur (fenbendazole, http://www.petplace.com/drug-library/fenbendazole-panacur/page1.aspx) ,
Tylosin (http://www.petplace.com/drug-library/tylosin-tylan/page1.aspx )
and even steroids (prednisone http://www.petplace.com/drug-library/prednisone-prednisolone/page1.aspx )
Now, as for what you can do for your dog. I suggest the following:
1. WITH-HOLD FOOD! Do not offer anything for 24 hours. This gives the intestines a chance to rest and heal.
2. When she is fasting, she can have lots of clear fluids. So, water is fine, but also she can have pedialyte, Gatorade, apple juice diluted 50:50 with water, or chicken or beef broth diluted 50:50 with water. Give the fluids in small amounts frequently. For a 25lb dog (just a guess on your dog's size?) this size that means about 1/2 cup an hour.
3. After 24 hours if the diarrhea has stopped, you can start your dog back on a bland diet. For patients that I see, I recommend a mixture of 75% cooked white rice, and 25% low fat protein. For the protein you could use extra lean ground beef, boiled with the fat scooped off, or chicken breast boiled with fat scooped off or even scrambled egg cooked without fat in the microwave. Feed small frequent meals. For a dog this size, I would suggest 2-3 tablespoons every 3 to 4 hours.
4. After 1-2 days on the rice mix, you would gradually change your dog back to the normal diet and food. So, on day 3, give the rice mixture, but bigger meals, spaced further apart. On day 4, mix a little tiny bit of the normal food in there, and decrease the frequency so it is down to 3 meals or so. And so on.
5. Keep your dog as quiet as possible - just out to relieve herself and back in.
I'll give you a link to further information:
So, my suggestion would be to try fasting today but giving lots of clear fluids.
If your girl is not keeping the fluids down, or develops very bloody stool, then do contact your veterinarian promptly!
I hope that helps you. If this has been helpful, please hit the green "Accept" button. I will still be here if you have further questions!