“I found these small, white worms in my horse’s water bucket in the barn”, writes Jennifer about the organisms pictured below. “I have seen them hanging from a thin thread they weave in his stall before. I am trying to identify them to make sure they aren’t toxic to him if he did ingest them. Thank you in advance.” First things first, we have to make clear that, given Jennifer’s concern for her horse’s health, any suggestions we make as to the identity of these worms should only be considered in light of these organisms being deemed non-threatening to the horse by a veterinarian. Since we are not medical professionals, we are neither qualified nor legally able to identify parasites or other organisms that directly impact the health of humans or pets, as doing so is tantamount to diagnosing their medical issue. So, we recommend that Jennifer asks a vet to check her horse and inspect the worms to see if they are a threat.