We recently received a question from a reader who found an interesting creature in her toilet. She found it a while after anyone had last used the toilet, so it is unlikely that it came from a human. She said she has done a lot of research, but has been unable to match it to anything she has discovered. She describes it as being small, “maybe 15 mm long and 2 mm thick.” It is smooth and cylindrical without any noticeable upper or lower side. Her description matches the photo quite well, but we would like to add that is a dark gray or brown color, and that it appears to be segmented. She hopes we can solve this mystery!

After looking at the photos, we are confident that she has found some sort of fly larva, but it is impossible to determine which family of fly this larva belongs to. Many different species of fly larva look almost identical, so a firm identification about the species of this larva is quite difficult. This being said, it is very likely that this is moth fly larva. Moth fly larvae generally look the same as the creature in the featured image, and their habitat is often moist with decaying organic matter (which matches a toilet).

To get rid of this creature (and to keep future ones at bay) we suggest that our reader sanitize her toilet using some toilet cleaner and a plunger or pipe brush! This will eliminate the food source and make the toilet less hospitable!

To wrap up, our reader found a species of what we believe to be either moth fly larva or a different type of fly larva in her toilet.

Originally posted 2015-11-24 10:05:13.