Now based on the signs we are seeing, we do have a few concerns for this soft stool. Common causes we need to consider include bacterial or viral gastroenteritis or colitis, parasites/protozoa infections, general dietary indiscretions, and ingestion of harmful items (ie toxins, plants, non-edible items). Just to note, the blood at the end of her stools will just be a sign that her colon is irritated and inflamed (as part of this or as a side effect). So, if we can normalize what she passes that too should settle.
With this all in mind, the rice was a good start. Though we do like to make this a bit more balanced, so consider adding a protein source like boiled chicken, boiled white fish, cottage cheese, scrambled eggs, or meat baby food (as long as its garlic/onion free). The aim of these diets is that they will be better tolerated/absorbed by the compromised gut to help normalize her stools. You can also add fiber (ie canned pumpkin, all bran) to these meals to help firm the stool further. As long as improvement is being seen, I usually advise that the diet be continued until her signs are settled, and that they are then slowly weaned back to their normal diet.
As well, since some worms and protozoa can cause blood and loose stools, you may want to re-worm her if it has been over a month. If you need to do so, consider using Panacur (Fenbendazole) since this will tackle a number of our worm concerns and helps with some of our protozoal concerns as well.
Finally, to further rebalance the gut and help form her stools you can consider a probiotic (ie Fortiflora). Or if she is very runny, then a probiotic/kaolin treatment would be ideal. Examples of these are Propectalin, Canikur, Fast Balance, and Protexin Pro-Fiber (which is available OTC at vets, pet stores, and even Amazon). They will slow loose stools and have that added bonus of providing support to the delicate good GI bacteria. So, these can be used as a short-term means of soothing this upset GI.
Overall, a wide range of agents could trigger the signs we are seeing. Therefore, in Mochi’s case, we’d want to start supportive care to settle her stomach. If she passes more blood, appears dehydrated already, or doesn’t respond to the above within 12-24 hours; then we'd want to get her vet involved. They can assess her hydration, test a stool sample, make sure there is nothing in her stomach that shouldn't be there or any sinister viruses present. Depending on their findings, her vet can treat her with antibiotics and symptomatic care as needed to settle her stomach, and get her back feeling like herself.
Please take care,