We just heard from a reader who has a pond that she swims in. She wrote that when they stand in the pond, they emerge with worm-like things sticking to their knees and below their feet. She continued that they also stick to the floaties, and they often just dry up and fall off. She said these “worms” are very small and range in color from clear to different shades of brown. What could these be?

We don’t have information about where this reader is from (location can sometimes be a huge clue in identifying species) and we don’t have any pictures to use for an appearance comparison. Therefore, it will be difficult to make a definite identification on what these creatures are. We will provide some potential answers though.

Horsehair worms are some of the most common worms that are found in swimming pools and ponds. They are parasitic to insects, boring into hosts and then ejecting from the hosts when they detect they are near water. They are not parasitic to humans. While this answer could be right, our reader said the worms were short, and horsehair worms can be quite long. They also often tangle themselves into knots, which is a pretty distinctive characteristic we believe our reader would have mentioned if she had seen it.

Another possibility is midge fly larvae. There are thousands of different species, all of which live in some sort of aquatic environment. The description of the specimens our reader described is a close match to this type of larvae, and they are also found in ponds! Mature midge flies are sometimes called “blind mosquitos”, but unlike mosquitos they don’t bite, suck blood, or carry diseases.

Although we cannot make a firm identification without a photograph or more details concerning the creatures’ behavior, we are pretty sure the “worms” she found in her pond are actually midge fly larvae.

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