simple question

I got a sea urchin the other day he doing great on the algee.But my fire /shunk/peppermint shrimp have been acting real wired. They wont leave it alone there allways inches from it and they do some werid side to side motion maybe i can flim it if we are geting the visual

Easy answer - the shrimp want to clean him but can’t figure out how.

Seen the side to side your talking about. Not sure why they do it, but I would consider it normal. What type of urchin is it?

long spined black

figured if it gets old i can eat him lol