How fast do rotifers swim?
 

I am starting a rotifer colony for the first time. I ordered live rotifers to get it going.

I seem to have many small slower moving critters in there, but then I also have larger ones, about the size of pods, much faster swimming ones in there.

My question is ... Are they just adults or is the colony contaminated?

Ok, so I have done some catching of things in my culture and then microscope work.

I thought I had several things "smaller than rotifer" and "larger than rotifer". It turns out that I found only one other thing in the culture in different stages of development.

I identified it as Tigriopus japonicus - copepod.

Now I am still worried having those in my rotifer only culture. Is that a problem?

Found the answer about contamination of cultures ...

https://www.jstage.jst.go.jp/article.../61_4_623/_pdf