TL;DR: Will red wigglers be able to fit between small clay pebbles in a growbed? If not, what will?
I have a very small DIY aquaponics media bed on top of my very small aquarium. My media bed is filled with 4mm-16mm clay pebbles. They're firmly held down by a sort of mesh, as otherwise they float (oops, live and learn). These are the pebbles: https://www.amazon.com/gp/product/B00CJIAGY6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
The spaces between the pebbles are slowly but surely filling up with roots and bits of solid matter, and water flow is starting to decrease a bit. I think I'd like to add some worms to do some solids breakdown. Red wigglers (Eisenia Foetida) are the species of worm everyone recommends for this job, but I'm a bit skeptical that they will actually be able to fit between the pebbles. Anyone have experience with this who could advise me? Will the red wigglers be able to squeeze in there? If not, is there another type of worm that would be more suitable? Thank you!
PS: I apologize if I've violated any guidelines - this is my first post.