“My mom found this worm in her cat’s water dish”, writes Jade in Atlanta, Georgia about the red, clear worm pictured below. “My mom said that it was not happy to be removed from the water/seemed like it belonged in water. We sent a photo to her vet and are waiting to hear back, but I am very curious what it is, even if it’s not a kitty parasite. Thanks so much! Attaching two photos and a video showing how it moves.” Firstly, we just want to thank Jade for the ample context and the excellent photo and video: they really help us narrow down the possible identifications for a given organism. Secondly, we have to say that, given that this was found in her cat’s water dish, we will not be able to give an identification that is 100% certain, given the possibility that it is related to the cat’s health – which Jade makes clear by affirming that she has consulted her vet. Since we are not medical professionals, we are neither qualified nor legally able to provide advice in these types of instances. Such advice includes making identifications. So, in the case that her vet decides that this worm is tied to her cat’s health, then Jade should disregard any of the information we give in this article.
With that said, in the case that the worm is not affecting her cat, and it did not come from the cat, then we would say this looks like a square-tailed worm (Eiseniella tetraedra). Oddly enough, not much is actually known about this worm, other than that it belongs to the same family that earthworms do, and that it is aquatic. Provided that this is a square-tailed worm, the fact that it thrives in aquatic habitats would explain Jade’s mom’s description of the worm not being “happy to be removed from the water”. She even stated that it “seemed like it belonged in water”, which is true of aquatic worm species. Square-tailed worms typically live in ponds, hiding under stones or in the mud and eating detritus, which is the organic debris produced by decomposing organisms. Like most species of earthworms, square-tailed worms help break down the organic materials they eat and clean up the waters they live in, and they also provide food for invertebrates further up the food chain.
If this truly is a square-tailed worm, we have no idea how it might have gotten into Jade’s cat’s water dish. If the cat is an outdoor cat, maybe it partially swallowed the worm during a drink of water from a pond, and spat it back up in its water dish? Or perhaps the water in the dish already had a square-tailed worm egg in it that hatched (though we think this is unlikely). In any case, the best advice we can give is that whatever identification the vet gives, trust that and follow their instructions.
To conclude, we cannot say with certainty what Jade’s mom found in their cat’s water dish. The reason for this is because we are not medical professionals and this is potentially a medical situation. In the case that it turns out not to be, we would guess that this is a square-tailed worm. We hope this helps and we wish Jade, her mom, and her cat, all the best.
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