Oozleanswered grow question 2 years ago Remove whatever it is by hand and use some bleach or pool shock to cleanse your system. Then I'd scrub and clean all your tubing and every bucket. Sanitize everything.
If it is a larvae or some bug, it is in your water and since you are using what looks like RDWC, your other plants have been exposed.
Cutting the roots will shock your plant and make it less able to fight off whatever you have. Also root trimming doesn't actually increase root mass. There are more root tips, but root mass stays the same, so cutting roots only slows down the plants. (There are some white papers on root trimming in hydro if you'd like to research it)
good luck.