Another mystery ciliate

[Free2Fish]

I captured this little guy zooming around my slide and finally decided to take an image and measure it. Turns out he comes in as a super lightweight at 5.6 um. None of my searches show any ciliate on the planet being smaller than 10 um. I agree the image is practically useless but is the best I've been able to get. You can definitely see the cilia whirling around as it scoots through the water.

[apochronaut]

Cilia are a widespread cellular mechanism for both locomotion and locomoting substances. There are ciliated reproductive bodies or lifecycle stages that mimic a ciliated organism in form. Flagellated too, some quite small. In the previous query for instance, I mentioned a blastocyte or more likely a blastodisc because there are species that temporarily utilize cilia on their primitive reproductive bodies as an effective mechanism for translocating the embryo. Some fish and I think some invertebrates too.
This little one, I don't have any idea about but it could be a reproductive body.

[Free2Fish]

Thanks, that makes sense.