“My friend’s hot tub hasn’t been cleaned since May”, writes this reader about the gray organism pictured below. “Was looking at it today and there are thousands of these clear, tadpole-like creatures swimming around. I’ll attach a video and picture. I’m from Fife, Scotland.” To start with, we have to point out how blurry this photo is. Because of this, we will not be able to give a confident identification of this creature. We are only guessing that the gray object in the photo is the tadpole-like organism our reader is referring to.